To make use of the new check_po.sh test, I have added a pre-commit git hook to my tails repository. i created a file called .git/hooks/pre-commit after looking at the default git example and put on it the content between lines:
--------------8<---------------8<-----------------
#!/bin/sh
# check translation files before commit
exec wiki/src/contribute/l10n_tricks/check_po.sh
--------------8<---------------8<-----------------
and voila! it does the check before commit.
remember: you need to have i18nspector installed and the git submodules updated:
https://tails.boum.org/contribute/git/#submodules
and then
https://tails.boum.org/contribute/l10n_tricks/#index5h1