Diff of the two buildlogs:

--
--- b1/build.log	2025-07-16 05:48:59.547513280 +0000
+++ b2/build.log	2025-07-16 05:50:46.691647674 +0000
@@ -1,6 +1,6 @@
 I: pbuilder: network access will be disabled during build
-I: Current time: Tue Aug 18 00:09:51 -12 2026
-I: pbuilder-time-stamp: 1787054991
+I: Current time: Wed Jul 16 19:49:01 +14 2025
+I: pbuilder-time-stamp: 1752644941
 I: Building the build Environment
 I: extracting base tarball [/var/cache/pbuilder/trixie-reproducible-base.tgz]
 I: copying local configuration
@@ -22,52 +22,84 @@
 dpkg-source: info: unpacking golang-github-buengese-sgzip_0.1.1-1.debian.tar.xz
 I: Not using root during the build.
 I: Installing the build-deps
-I: user script /srv/workspace/pbuilder/2468280/tmp/hooks/D02_print_environment starting
+I: user script /srv/workspace/pbuilder/1410794/tmp/hooks/D01_modify_environment starting
+debug: Running on ionos1-amd64.
+I: Changing host+domainname to test build reproducibility
+I: Adding a custom variable just for the fun of it...
+I: Changing /bin/sh to bash
+'/bin/sh' -> '/bin/bash'
+lrwxrwxrwx 1 root root 9 Jul 16 05:49 /bin/sh -> /bin/bash
+I: Setting pbuilder2's login shell to /bin/bash
+I: Setting pbuilder2's GECOS to second user,second room,second work-phone,second home-phone,second other
+I: user script /srv/workspace/pbuilder/1410794/tmp/hooks/D01_modify_environment finished
+I: user script /srv/workspace/pbuilder/1410794/tmp/hooks/D02_print_environment starting
 I: set
-  BUILDDIR='/build/reproducible-path'
-  BUILDUSERGECOS='first user,first room,first work-phone,first home-phone,first other'
-  BUILDUSERNAME='pbuilder1'
-  BUILD_ARCH='amd64'
-  DEBIAN_FRONTEND='noninteractive'
-  DEB_BUILD_OPTIONS='buildinfo=+all reproducible=+all parallel=42 '
-  DISTRIBUTION='trixie'
-  HOME='/root'
-  HOST_ARCH='amd64'
+  BASH=/bin/sh
+  BASHOPTS=checkwinsize:cmdhist:complete_fullquote:extquote:force_fignore:globasciiranges:globskipdots:hostcomplete:interactive_comments:patsub_replacement:progcomp:promptvars:sourcepath
+  BASH_ALIASES=()
+  BASH_ARGC=()
+  BASH_ARGV=()
+  BASH_CMDS=()
+  BASH_LINENO=([0]="12" [1]="0")
+  BASH_LOADABLES_PATH=/usr/local/lib/bash:/usr/lib/bash:/opt/local/lib/bash:/usr/pkg/lib/bash:/opt/pkg/lib/bash:.
+  BASH_SOURCE=([0]="/tmp/hooks/D02_print_environment" [1]="/tmp/hooks/D02_print_environment")
+  BASH_VERSINFO=([0]="5" [1]="2" [2]="37" [3]="1" [4]="release" [5]="x86_64-pc-linux-gnu")
+  BASH_VERSION='5.2.37(1)-release'
+  BUILDDIR=/build/reproducible-path
+  BUILDUSERGECOS='second user,second room,second work-phone,second home-phone,second other'
+  BUILDUSERNAME=pbuilder2
+  BUILD_ARCH=amd64
+  DEBIAN_FRONTEND=noninteractive
+  DEB_BUILD_OPTIONS='buildinfo=+all reproducible=+all parallel=40 '
+  DIRSTACK=()
+  DISTRIBUTION=trixie
+  EUID=0
+  FUNCNAME=([0]="Echo" [1]="main")
+  GROUPS=()
+  HOME=/root
+  HOSTNAME=i-capture-the-hostname
+  HOSTTYPE=x86_64
+  HOST_ARCH=amd64
   IFS=' 	
   '
-  INVOCATION_ID='0c8c5c0e431b4e4c86ab653f56a28f6d'
-  LANG='C'
-  LANGUAGE='en_US:en'
-  LC_ALL='C'
-  MAIL='/var/mail/root'
-  OPTIND='1'
-  PATH='/usr/sbin:/usr/bin:/sbin:/bin:/usr/games'
-  PBCURRENTCOMMANDLINEOPERATION='build'
-  PBUILDER_OPERATION='build'
-  PBUILDER_PKGDATADIR='/usr/share/pbuilder'
-  PBUILDER_PKGLIBDIR='/usr/lib/pbuilder'
-  PBUILDER_SYSCONFDIR='/etc'
-  PPID='2468280'
-  PS1='# '
-  PS2='> '
+  INVOCATION_ID=2966d666d44347d1bc17af369e802ee9
+  LANG=C
+  LANGUAGE=et_EE:et
+  LC_ALL=C
+  MACHTYPE=x86_64-pc-linux-gnu
+  MAIL=/var/mail/root
+  OPTERR=1
+  OPTIND=1
+  OSTYPE=linux-gnu
+  PATH=/usr/sbin:/usr/bin:/sbin:/bin:/usr/games:/i/capture/the/path
+  PBCURRENTCOMMANDLINEOPERATION=build
+  PBUILDER_OPERATION=build
+  PBUILDER_PKGDATADIR=/usr/share/pbuilder
+  PBUILDER_PKGLIBDIR=/usr/lib/pbuilder
+  PBUILDER_SYSCONFDIR=/etc
+  PIPESTATUS=([0]="0")
+  POSIXLY_CORRECT=y
+  PPID=1410794
   PS4='+ '
-  PWD='/'
-  SHELL='/bin/bash'
-  SHLVL='2'
-  SUDO_COMMAND='/usr/bin/timeout -k 18.1h 18h /usr/bin/ionice -c 3 /usr/bin/nice /usr/sbin/pbuilder --build --configfile /srv/reproducible-results/rbuild-debian/r-b-build.s8MV0QuW/pbuilderrc_x8Rk --distribution trixie --hookdir /etc/pbuilder/first-build-hooks --debbuildopts -b --basetgz /var/cache/pbuilder/trixie-reproducible-base.tgz --buildresult /srv/reproducible-results/rbuild-debian/r-b-build.s8MV0QuW/b1 --logfile b1/build.log golang-github-buengese-sgzip_0.1.1-1.dsc'
-  SUDO_GID='111'
-  SUDO_UID='106'
-  SUDO_USER='jenkins'
-  TERM='unknown'
-  TZ='/usr/share/zoneinfo/Etc/GMT+12'
-  USER='root'
-  _='/usr/bin/systemd-run'
-  http_proxy='http://213.165.73.152:3128'
+  PWD=/
+  SHELL=/bin/bash
+  SHELLOPTS=braceexpand:errexit:hashall:interactive-comments:posix
+  SHLVL=3
+  SUDO_COMMAND='/usr/bin/timeout -k 24.1h 24h /usr/bin/ionice -c 3 /usr/bin/nice -n 11 /usr/bin/unshare --uts -- /usr/sbin/pbuilder --build --configfile /srv/reproducible-results/rbuild-debian/r-b-build.s8MV0QuW/pbuilderrc_HA4e --distribution trixie --hookdir /etc/pbuilder/rebuild-hooks --debbuildopts -b --basetgz /var/cache/pbuilder/trixie-reproducible-base.tgz --buildresult /srv/reproducible-results/rbuild-debian/r-b-build.s8MV0QuW/b2 --logfile b2/build.log golang-github-buengese-sgzip_0.1.1-1.dsc'
+  SUDO_GID=110
+  SUDO_UID=105
+  SUDO_USER=jenkins
+  TERM=unknown
+  TZ=/usr/share/zoneinfo/Etc/GMT-14
+  UID=0
+  USER=root
+  _='I: set'
+  http_proxy=http://46.16.76.132:3128
 I: uname -a
-  Linux ionos15-amd64 6.12.32+bpo-amd64 #1 SMP PREEMPT_DYNAMIC Debian 6.12.32-1~bpo12+1 (2025-06-21) x86_64 GNU/Linux
+  Linux i-capture-the-hostname 6.1.0-37-amd64 #1 SMP PREEMPT_DYNAMIC Debian 6.1.140-1 (2025-05-22) x86_64 GNU/Linux
 I: ls -l /bin
-  lrwxrwxrwx 1 root root 7 May 12  2025 /bin -> usr/bin
-I: user script /srv/workspace/pbuilder/2468280/tmp/hooks/D02_print_environment finished
+  lrwxrwxrwx 1 root root 7 May 12 19:25 /bin -> usr/bin
+I: user script /srv/workspace/pbuilder/1410794/tmp/hooks/D02_print_environment finished
  -> Attempting to satisfy build-dependencies
  -> Creating pbuilder-satisfydepends-dummy package
 Package: pbuilder-satisfydepends-dummy
@@ -146,7 +178,7 @@
 Get: 35 http://deb.debian.org/debian trixie/main amd64 golang-any amd64 2:1.24~2 [5216 B]
 Get: 36 http://deb.debian.org/debian trixie/main amd64 golang-github-cespare-xxhash-dev all 2.3.0-1 [10.8 kB]
 Get: 37 http://deb.debian.org/debian trixie/main amd64 golang-github-klauspost-compress-dev all 1.18.0+ds1-1 [33.3 MB]
-Fetched 94.5 MB in 1s (66.2 MB/s)
+Fetched 94.5 MB in 1s (86.4 MB/s)
 Preconfiguring packages ...
 Selecting previously unselected package sensible-utils.
 (Reading database ... 
(Reading database ... 5%
(Reading database ... 10%
(Reading database ... 15%
(Reading database ... 20%
(Reading database ... 25%
(Reading database ... 30%
(Reading database ... 35%
(Reading database ... 40%
(Reading database ... 45%
(Reading database ... 50%
(Reading database ... 55%
(Reading database ... 60%
(Reading database ... 65%
(Reading database ... 70%
(Reading database ... 75%
(Reading database ... 80%
(Reading database ... 85%
(Reading database ... 90%
(Reading database ... 95%
(Reading database ... 100%
(Reading database ... 19850 files and directories currently installed.)
@@ -309,7 +341,11 @@
 Building tag database...
  -> Finished parsing the build-deps
 I: Building the package
-I: Running cd /build/reproducible-path/golang-github-buengese-sgzip-0.1.1/ && env PATH="/usr/sbin:/usr/bin:/sbin:/bin:/usr/games" HOME="/nonexistent/first-build" dpkg-buildpackage -us -uc -b && env PATH="/usr/sbin:/usr/bin:/sbin:/bin:/usr/games" HOME="/nonexistent/first-build" dpkg-genchanges -S  > ../golang-github-buengese-sgzip_0.1.1-1_source.changes
+I: user script /srv/workspace/pbuilder/1410794/tmp/hooks/A99_set_merged_usr starting
+Not re-configuring usrmerge for trixie
+I: user script /srv/workspace/pbuilder/1410794/tmp/hooks/A99_set_merged_usr finished
+hostname: Name or service not known
+I: Running cd /build/reproducible-path/golang-github-buengese-sgzip-0.1.1/ && env PATH="/usr/sbin:/usr/bin:/sbin:/bin:/usr/games:/i/capture/the/path" HOME="/nonexistent/second-build" dpkg-buildpackage -us -uc -b && env PATH="/usr/sbin:/usr/bin:/sbin:/bin:/usr/games:/i/capture/the/path" HOME="/nonexistent/second-build" dpkg-genchanges -S  > ../golang-github-buengese-sgzip_0.1.1-1_source.changes
 dpkg-buildpackage: info: source package golang-github-buengese-sgzip
 dpkg-buildpackage: info: source version 0.1.1-1
 dpkg-buildpackage: info: source distribution unstable
@@ -327,38 +363,38 @@
    dh_autoreconf -O--builddirectory=_build -O--buildsystem=golang
    dh_auto_configure -O--builddirectory=_build -O--buildsystem=golang
    dh_auto_build -O--builddirectory=_build -O--buildsystem=golang
-	cd _build && go install -trimpath -v -p 42 github.com/buengese/sgzip
+	cd _build && go install -trimpath -v -p 40 github.com/buengese/sgzip
+internal/goarch
 internal/coverage/rtcov
-cmp
 internal/itoa
-internal/byteorder
-internal/msan
-internal/godebugs
+cmp
+github.com/klauspost/compress/internal/le
 internal/asan
-internal/profilerecord
-internal/goos
+internal/godebugs
 internal/unsafeheader
-github.com/klauspost/compress/internal/le
+internal/profilerecord
+internal/msan
+unicode/utf8
 math/bits
-internal/goarch
+internal/runtime/syscall
+internal/goos
+internal/byteorder
 unicode
 internal/goexperiment
-internal/runtime/syscall
-internal/cpu
 sync/atomic
+internal/cpu
 internal/runtime/atomic
-unicode/utf8
 internal/runtime/math
-internal/runtime/sys
 internal/abi
+internal/runtime/sys
 internal/chacha8rand
 internal/runtime/exithook
 internal/bytealg
 math
+internal/stringslite
 internal/race
 internal/sync
 internal/runtime/maps
-internal/stringslite
 runtime
 iter
 internal/reflectlite
@@ -366,12 +402,12 @@
 slices
 errors
 sort
+internal/bisect
+internal/testlog
 internal/oserror
 path
-strconv
-internal/testlog
-internal/bisect
 io
+strconv
 syscall
 internal/godebug
 hash
@@ -381,20 +417,20 @@
 reflect
 bufio
 internal/syscall/execenv
-time
 internal/syscall/unix
+time
 io/fs
 internal/poll
 internal/filepathlite
-os
 internal/fmtsort
 encoding/binary
+os
 fmt
 compress/flate
 github.com/klauspost/compress/flate
 github.com/buengese/sgzip
    dh_auto_test -O--builddirectory=_build -O--buildsystem=golang
-	cd _build && go test -vet=off -v -p 42 github.com/buengese/sgzip
+	cd _build && go test -vet=off -v -p 40 github.com/buengese/sgzip
 === RUN   TestDecompressor
 --- PASS: TestDecompressor (0.02s)
 === RUN   TestSeekUnseekable
@@ -409,9 +445,9 @@
 === RUN   TestReaderAt
 --- PASS: TestReaderAt (0.00s)
 === RUN   TestDecompressFileWithSeek
---- PASS: TestDecompressFileWithSeek (0.31s)
+--- PASS: TestDecompressFileWithSeek (0.23s)
 === RUN   TestMultiSeek
---- PASS: TestMultiSeek (0.04s)
+--- PASS: TestMultiSeek (0.02s)
 === RUN   TestIssue6550
     gunzip_test.go:570: Copy failed (correctly): flate: corrupt input before offset 3
 --- PASS: TestIssue6550 (0.00s)
@@ -428,9 +464,9 @@
 === RUN   TestTruncatedGunzip
 --- PASS: TestTruncatedGunzip (0.01s)
 === RUN   TestTruncatedGunzipBlocks
---- PASS: TestTruncatedGunzipBlocks (0.03s)
+--- PASS: TestTruncatedGunzipBlocks (0.02s)
 === RUN   TestAllocations
-    gzip_norace_test.go:31: Allocated 693 bytes per Write on average
+    gzip_norace_test.go:31: Allocated 1012 bytes per Write on average
 --- PASS: TestAllocations (0.08s)
 === RUN   TestEmpty
 --- PASS: TestEmpty (0.00s)
@@ -445,7 +481,7 @@
 === RUN   TestWriterFlush
 --- PASS: TestWriterFlush (0.00s)
 === RUN   TestConcat
---- PASS: TestConcat (0.01s)
+--- PASS: TestConcat (0.00s)
 === RUN   TestWriterReset
 --- PASS: TestWriterReset (0.00s)
 === RUN   TestFile1
@@ -453,9 +489,9 @@
 === RUN   TestFile10
 --- PASS: TestFile10 (0.02s)
 === RUN   TestFile50
---- PASS: TestFile50 (0.08s)
+--- PASS: TestFile50 (0.09s)
 === RUN   TestFile200
---- PASS: TestFile200 (0.32s)
+--- PASS: TestFile200 (0.35s)
 === RUN   TestGzip1K
 --- PASS: TestGzip1K (0.00s)
 === RUN   TestGzip100K
@@ -469,23 +505,23 @@
 === RUN   TestDeterministicBlockLM2
 --- PASS: TestDeterministicBlockLM2 (0.22s)
 === RUN   TestDeterministicL0
---- PASS: TestDeterministicL0 (0.22s)
+--- PASS: TestDeterministicL0 (0.24s)
 === RUN   TestDeterministicBlockL0
---- PASS: TestDeterministicBlockL0 (0.21s)
+--- PASS: TestDeterministicBlockL0 (0.22s)
 === RUN   TestDeterministicL1
 --- PASS: TestDeterministicL1 (0.26s)
 === RUN   TestDeterministicBlockL1
---- PASS: TestDeterministicBlockL1 (0.30s)
+--- PASS: TestDeterministicBlockL1 (0.26s)
 === RUN   TestDeterministicL2
---- PASS: TestDeterministicL2 (0.27s)
+--- PASS: TestDeterministicL2 (0.26s)
 === RUN   TestDeterministicBlockL2
---- PASS: TestDeterministicBlockL2 (0.28s)
+--- PASS: TestDeterministicBlockL2 (0.26s)
 === RUN   TestDeterministicL3
---- PASS: TestDeterministicL3 (0.28s)
+--- PASS: TestDeterministicL3 (0.27s)
 === RUN   TestDeterministicBlockL3
 --- PASS: TestDeterministicBlockL3 (0.27s)
 === RUN   TestDeterministicL4
---- PASS: TestDeterministicL4 (0.27s)
+--- PASS: TestDeterministicL4 (0.26s)
 === RUN   TestDeterministicBlockL4
 --- PASS: TestDeterministicBlockL4 (0.26s)
 === RUN   TestDeterministicL5
@@ -495,19 +531,19 @@
 === RUN   TestDeterministicL6
 --- PASS: TestDeterministicL6 (0.29s)
 === RUN   TestDeterministicBlockL6
---- PASS: TestDeterministicBlockL6 (0.30s)
+--- PASS: TestDeterministicBlockL6 (0.32s)
 === RUN   TestDeterministicL7
---- PASS: TestDeterministicL7 (0.46s)
+--- PASS: TestDeterministicL7 (0.49s)
 === RUN   TestDeterministicBlockL7
---- PASS: TestDeterministicBlockL7 (0.45s)
+--- PASS: TestDeterministicBlockL7 (0.44s)
 === RUN   TestDeterministicL8
 --- PASS: TestDeterministicL8 (0.44s)
 === RUN   TestDeterministicBlockL8
---- PASS: TestDeterministicBlockL8 (0.45s)
+--- PASS: TestDeterministicBlockL8 (0.44s)
 === RUN   TestDeterministicL9
 --- PASS: TestDeterministicL9 (0.90s)
 === RUN   TestDeterministicBlockL9
---- PASS: TestDeterministicBlockL9 (0.96s)
+--- PASS: TestDeterministicBlockL9 (0.90s)
 === RUN   TestErrors
 --- PASS: TestErrors (0.00s)
 === RUN   TestWriteError
@@ -521,9 +557,9 @@
 === RUN   TestWriteError/level-7
 === RUN   TestWriteError/level-8
 === RUN   TestWriteError/level-9
---- PASS: TestWriteError (0.12s)
-    --- PASS: TestWriteError/level-0 (0.01s)
-    --- PASS: TestWriteError/level-1 (0.00s)
+--- PASS: TestWriteError (0.11s)
+    --- PASS: TestWriteError/level-0 (0.00s)
+    --- PASS: TestWriteError/level-1 (0.01s)
     --- PASS: TestWriteError/level-2 (0.01s)
     --- PASS: TestWriteError/level-3 (0.01s)
     --- PASS: TestWriteError/level-4 (0.01s)
@@ -533,7 +569,7 @@
     --- PASS: TestWriteError/level-8 (0.02s)
     --- PASS: TestWriteError/level-9 (0.02s)
 PASS
-ok  	github.com/buengese/sgzip	9.333s
+ok  	github.com/buengese/sgzip	9.141s
    create-stamp debian/debhelper-build-stamp
    dh_testroot -O--builddirectory=_build -O--buildsystem=golang
    dh_prep -O--builddirectory=_build -O--buildsystem=golang
@@ -561,12 +597,14 @@
 dpkg-buildpackage: info: binary-only upload (no source included)
 dpkg-genchanges: info: including full source code in upload
 I: copying local configuration
+I: user script /srv/workspace/pbuilder/1410794/tmp/hooks/B01_cleanup starting
+I: user script /srv/workspace/pbuilder/1410794/tmp/hooks/B01_cleanup finished
 I: unmounting dev/ptmx filesystem
 I: unmounting dev/pts filesystem
 I: unmounting dev/shm filesystem
 I: unmounting proc filesystem
 I: unmounting sys filesystem
 I: cleaning the build env 
-I: removing directory /srv/workspace/pbuilder/2468280 and its subdirectories
-I: Current time: Tue Aug 18 00:11:58 -12 2026
-I: pbuilder-time-stamp: 1787055118
+I: removing directory /srv/workspace/pbuilder/1410794 and its subdirectories
+I: Current time: Wed Jul 16 19:50:46 +14 2025
+I: pbuilder-time-stamp: 1752645046