Description
By mistake or affected by changes of engine/format/package(s), a duplicative engine-specific test output (e.g., <name>.<engine>.tlg) may be created or a once necessary engine-specific test output may become unnecessary. It would be useful if l3build can list duplicative engine-specific test outputs.
For example, testfiles/api-tag-too-long.luatex.tlg in repository latex3/fontspec was once needed but now duplicative (identical to testfiles/api-tag-too-long.tlg), see this job log and latex3/fontspec@36344e8.
Such unnecessary test outputs even once existed in latex3 repositories, see latex3/latex2e@5daacc181 (drop unnecessary .tlgs (if my script is correct), 2025-01-28).
A new option --show-dup which simply print a list at the end of l3build save and l3build check? Or stricter, like --no-dup which throws an error on duplication.