Difference between two '$template' arguments in 'merge_sphinx_po()' of update.sh?

[hwhsu1231]

Hello, godot-docs-l10n Development Team.

I noticed that there are two $template arguments specified to msgmerge command in merge_sphinx_po() of update.sh:

msgmerge --lang="$lang" --no-location -C "$po" "$template" "$template" -o "$output"

https://github.com/godotengine/godot-docs-l10n/blob/b1c660f7f1da05d1755d4492c0a9cc7d544db8c2/update.sh#L144

I wonder that what's the difference between these two $template arguments?