I'm checking my TeX installation and it appears that I have TeXLive
2019, the basic version.
If you mean you installed the native TeX Live (tug.org/texlive), not any
distro version,
(1) the files are in, for example:
/usr/local/texlive/2019/texmf-dist/tex/texinfo/txi-fr.tex
(2) if you don't have anything there, running
tlmgr install texinfo
should get them installed. ("texinfo" in the TeX Live world is just the
TeX-related files; no binaries are installed and nothing outside the TL
directory is touched.)
However, if you're running a distro TeX, above is inapplicable. --best, karl.
