In GNOME, there are several cases when things such as filenames are included in messages. Messages like "Really delete '%s'?" that include these create problems (in both LTR and RTL languages) when the filename itself changes direction.

For example, if a certain file name may be "/etc/passwd", a Persian translation of that message should make sure to include an LRM before the %s that represents the filename or embed the %s in an LRE-PDF pair. But this will not work if the filename could also be an RTL or bidirectional string. This also happens with the English UI and an RTL or bidi string.

This is not only for files, but for any string that is displayed both independetly in the user interface and its direction is discovered automatically, and also as a part of another string.

Pango needs to have some way (possibly using the Text Attribute Markup Language to minimize changes in the applications) to mark a section of the text as a *neutral embedding*. The best place to implemente this would have been the Unicode Bidirectional Algorithm, but as that is considered somehow frozen, we need to do it ourselves.

It may work somehow like this: When encountering a string like "A<bn>bC<bn>D</bn></bn>" (where capital letters stand for RTL letters), it would render the string as it was "A<LRE>bC<RLE>D<PDF><PDF>".