A code comment shows up as a translator comment
#. A list containing the names of all savestates with name of the form "New Savestate %d"
#: src/retro/retro-runner.vala:620 src/retro/retro-runner.vala:646
#, c-format
msgid "New savestate %s"
msgstr ""
This comment makes no sense in the po file. It should be either removed or replaced with a proper translator comment explaining what the %s
there is.