Hello troffers! English is not my native language, so please take this into account.
In the current edition of groff.texinfo (Edition 1.21, Winter 2010) it reads unter section '5.21 Writing Macros': "The optional second argument to de changes this to a macro to ‘.end’." For me this sentence is difficult to understand, although the meaning is obvious. It means that the optional second argument to de changes this to a macro definition until the request '.end' is encountered instead of the default '..'. I can't decide if the sentence as it is currently printed in the manual is perfectly understandable for a native speaker... if so, please disregard this mail. ;) Best regards Ralph