There is a serious problem with this string:

#: ../src/PhotoVersionCommands.cs:196
#, csharp-format
msgid "Really reparent \"{2}\" as version of \"{1}\"?"
msgid_plural "Really reparent {0} photos as versions of \"{1}\"?"

This can not be translated, because the singular form contains the {2} variable instead of {1}. gettext gives an error if I translate it, for example:

$ grep -A5 PhotoVersionCommands.cs:196 po/hu.po 
#: ../src/PhotoVersionCommands.cs:196
#, csharp-format
msgid "Really reparent \"{2}\" as version of \"{1}\"?"
msgid_plural "Really reparent {0} photos as versions of \"{1}\"?"
msgstr[0] "Really reparent \"{2}\" as version of \"{1}\"?"
msgstr[1] "Really reparent {0} photos as versions of \"{1}\"?"

$ msgfmt -cv po/hu.po 
po/hu.po:2784: number of format specifications in 'msgid' and 'msgstr[0]' does not match
msgfmt: found 1 fatal error

And because Gnome's git is clever, it does not allow us to commit "faulty" po files.

Please change the code to inlcude {0} in the singular message.