It's not only the license files, but the fonts are not installed either. That's despite the .tspec referring to them.
This breaks meson-based build from tarball also in S3_1 -> S3_1-alpha4 blocker.
Patch version also for S2_6 attached - fixing also sdl-client theme.
Crosser meson-build_all_installers.sh fails on master when building from tarball.
../../../meson.build:3021:0: ERROR: File data/themes/gui-sdl2/human/COPYING.fireflysung does not exist.
That such a problem has not come up before, hints that autotools based build does not even try to install that license file.