This is not a correction, just a suggested change for --IMHO-- better readability. If you prefer to keep this as it is, no problem.
$ diff -u groff.texi.orig groff.texi --- groff.texi.orig 2024-03-05 18:20:59.940460376 +0000 +++ groff.texi 2024-03-07 02:16:01.493119683 +0000 @@ -5362,9 +5362,9 @@ .ENDNAME @endExample -In fact, the ending marker is itself the name of a macro to be -called, or a request to be invoked, if it is defined at the time its -control line is read. +In fact, the ending marker can itself be the name of another macro to be +called, or a request to be invoked, provided this is already defined by the +time the control line containing the ending marker is read. @Example .de END