As per https://github.com/trufont/trufont/issues/44#issuecomment-149946491 when someone exports a font from GlyphsApp, it would be good if instead of as in https://github.com/huertatipografica/sura/blob/master/fonts/Sura-Regular.ufo/metainfo.plist the creator value is com.schriftgestaltung.GlyphsUFOExport it had the build version also, eg com.schriftgestaltung.GlyphsUFOExport.768
I would suggest an extra field in the metainfo file instead of adding the version number to the creator. Those fields are mostly not preserved on opening/re-saving so compatibility is not really an issue.
UFO spec is frozen so no extra fields are possible.
The lack of preservation is totally acceptable - intended, even! 
Its just informative to know which program created that particular version of the file.
I meant in this file it would be no problem to add an entry as it would go away anyway?
Shipping non-spec-compliant UFO data is a bit gross… but since the file will likely be rewritten by any tool that touches the file, maybe this isn’t a big deal…
The idea was to have a unique name in creator that doesn’t change (that a importer can react to it) and to put the version information somewhere else. But that might not be so important.
That can still work with a simple regex; but yes, perhaps somewhere else is better for this information.