• Read every file under debian/ (control, rules, changelog, copyright, docs, gbp.conf, salsa-ci.yml, gitlab-ci.yml, lrc.config, source/format, source/lintian-overrides, patches/series and 0001-add-go-mod.patch, upstream/metadata), and every upstream file in full except single_byte.go and multi_byte.go, whose heads and provenance I read and whose contents I grepped; the whole tree was grepped for copyright, licence and provenance wording.
• Tree inventory: the orig tarball holds 13 files (2022.go, AUTHORS, detector.go, detector_test.go, example_test.go, icu-license.html, LICENSE, multi_byte.go, README.md, recognizer.go, single_byte.go, unicode.go, utf8.go); the unpacked tree adds only go.mod, which comes from debian/patches/0001-add-go-mod.patch. testdata/ is absent, exactly as Files-Excluded: testdata declares, so the excluded files' licensing cannot affect the package.
• Licence evidence: no .go file carries a copyright or licence header; the only licence statements in the tree are LICENSE (Expat, Copyright (c) 2012 chardet Authors, plus the pointer to icu-license.html) and icu-license.html (ICU License, Copyright (c) 1995-2012 International Business Machines Corporation and others). Both licences are free and compatible, and debian/copyright reproduces both texts completely; neither is in /usr/share/common-licenses, so including them is required.
• Prescan: the author check reports no missing holder (14 files scanned, 3 holders declared). The IBM notice it looked for at icu-license.html:14 is now in the Files: * Copyright and in the dedicated Files: icu-license.html stanza with License: ICU.
• debian/copyright is DEP-5 with the canonical Format: URI: header Comment and Files-Excluded are permitted (copyright-format 5.1, 6.6), the specific icu-license.html and debian/* stanzas follow Files: * so they override it (copyright-format 6.9), and both short names used (Expat, ICU) have stand-alone paragraphs.
• single_byte.go:782-881 holds the charMap_/ngrams_ tables the copyright comment attributes to ICU's data; there is no generated/DO-NOT-EDIT marker and no go:generate, and no generator input is referenced. The tree contains only text files - Go source, Markdown, the HTML licence and control/changelog/YAML - with no binaries, fonts, images, PDFs, minified code or archives.
• debian/lrc.config is the per-package licenserecon configuration (documented in /usr/share/doc/licenserecon/ReadMe and /usr/share/lrc/lrc.config); Expat and ICU | ICU is a licence-name alias for what licensecheck reports for icu-license.html, not an exclusion that hides a mismatch.
• Build dependencies exist: dh-go 1.69 (provides the golang addon, buildsystem and dh_golang_autopkgtest; Conflicts dh-golang and Provides no dh-sequence-golang, so the source/lintian-overrides entry is justified), dpkg-build-api (= 1) from dpkg-dev 1.23.11, and golang-any 2:1.27~1. The source imports only the standard library and its own module path, so go.mod correctly needs no require.
• Standards-Version 4.7.4 against Policy 4.7.4.1 is current (first two components equal). At compat 14 the bare Depends: ${misc:Depends}, is complete, and dpkg-build-api 1 makes Rules-Requires-Root default to no.
• The one patch has a DEP-3 header (Description, Author, Forwarded: not-needed, Last-Update), adds only a three-line go.mod, is listed in patches/series and is applied in the tree. XS-Go-Import-Path matches the module path; Homepage, Vcs-Git/Vcs-Browser, Section: golang, Architecture: all and Multi-Arch: foreign are consistent with pkg-go practice.
• The rules' test override passes -skip TestDetector (a Go >= 1.20 flag; golang-any here is 1.27), so build-time go test skips the testdata-reading detector test and still runs ExampleTextDetector, and the comment and debian/copyright give the same reason. The installed dh_golang_autopkgtest rebuilds through make -f debian/rules build, so the override also governs its test step - subject to the build-directory question under Not confirmed.
• No maintainer scripts and no debian/tests/ (Testsuite: autopkgtest-pkg-go with autodep8's go template is the pkg-go mechanism); source format 3.0 (quilt); the changelog is a single unstable initial entry closing the ITP, with a version matching the dsc.
• uscan found the packaged version as the newest upstream release (upstream 0.0~git20230101.5e3ef4b, packaged 0.0~git20230101.5e3ef4b+dfsg).

• golang-github-gogits-chardet-dev Provides golang-github-saintfish-chardet-dev (apt-cache) and its description links godoc.org/github.com/saintfish/chardet, which suggests it installs sources under /usr/share/gocode/src/github.com/saintfish/chardet. If it does, the two packages install the same path with different contents and this package declares no Replaces/Breaks/Conflicts; I could not list that package's files to decide it.
• Whether the autopkgtest can build this package: the installed dh_golang_autopkgtest (from dh-golang 1.67, /usr/bin/dh_golang_autopkgtest) computes APT_BDIR as load_buildsystem('golang')->get_builddir(), which is the compat-14 default _build (Buildsystem/golang.pm DEFAULT_BUILD_DIRECTORY, Dh_Buildsystems.pm), while debian/rules builds in debian/_build; its added override would populate _build and dh_auto_build would then fail with chdir("debian/_build") failed. dh-go 1.69, which autopkgtest would install through Build-Depends, ships its own copy of the script that was not readable here; a test run would show whether it shares this, and using the default _build in debian/rules would remove the risk.

None.