The translation toolchain picks up the schema.org data into po-files. For example: #: opac-tmpl/bootstrap/en/xslt/MARC21slim2OPACDetail.xsl:100 #, c-format msgid "MusicAlbum" msgstr "" #: opac-tmpl/bootstrap/en/xslt/MARC21slim2OPACDetail.xsl:1026 #, c-format msgid "MusicGroup" msgstr "" These should not be translatable.