Sitemaps differ from regular pages in two respects:
Also, sitemaps contain many translatable messages, so it is desirable to eliminate manual work where possible.
In order to take this into account, GNUN provides the
variable in gnun.mk. All articles listed in
rebuilt using an additional compendium (when present),
Those additional compendia are supposed to be compiled outside of GNUN
by the same tool that generates the sitemap. It is the responsibility of
that tool to provide the compendia with reasonable translations whose
msgids match those generated by PO4A when processing the
English version of the sitemap.