Localization fail.

Meson build script not generate msg's files. But the latest gitk doesn't localized with /usr/share/locale/%{lang}/LC_MESSAGE/gitk.mo files.

Build from git release tarball v2.51.0 bundled with gitk and git-gui.
Tcl(Tk) v8.6.15

The Meson build of Gitk is not yet wired up to the Meson build of Git. Whether or not this is the reason for your observation, I cannot tell since I have no knowledge of Meson whatsoever.