The GNU Free System Distribution Guidelines considers chromium itself to be not-compliant because it is a huge, huge heap of code which contains e.g. non-libre code for unrar, various media codecs that require it to be built with --enable-proprietary-codecs, and generally code that has "unknown licensing". It is an 11 year old project which was not, originally, proactive about double-checking the licenses and dotting all the i's and crossing all the t's, so it is plausible there are interesting things lurking in corners.
https://libreplanet.org/wiki/List_of...romium-browser
Its status is officially "unclear, therefore the GNU FSDG refuses to condone it". Some distributions take it on faith that Chromium developers say they have the right to all the code (minus obvious things like proprietary codecs or third_party/unrar/src/*.cpp) while others reject it entirely.
The standard reference for chromium (the place where the discussion about this issue began) is
https://bugs.chromium.org/p/chromium...etail?id=28291
...
Qt WebEngine is another kettle of fish entirely. And here, FSDG-compliant Linux distributions are under the impression that WebEngine "embeds all of Chromium" and should therefore be tarred with the same brush as Chromium (whatever that brush may be, currently it is "I don't trust the licenses to be complete"). Meanwhile the Qt and KDE developers claim they disable and strip out tons of source, and the parts that they keep -- mostly lower level stuff -- aren't problematic even if Chromium itself is. Some background:
https://labs.parabola.nu/issues/1167
https://bugs.kde.org/show_bug.cgi?id=374808#c4
https://lists.qt-project.org/piperma...ry/000409.html