Rombug?

[Elena Zannoni <ezannoni at cygnus dot com>]

While cleaning up the syntax for add-symbol-file, I saw that that
command has a special syntax just for the rombug case.  For rombug, one
doesn't need to specify the address of the .text section to load the
file at. For all the other cases, such address must instead be specified as
argument to the command.  Needless to say, this little variation
complicates things quite a bit.
 
When is rombug used and what exactly is it? There is a brief mention of
it in the gdb manual, but not enough for me to understand much.
Is it still in use? 
 
Thanks
Elena