Your bug report

#39254: 26.3 and 27.0.50; The manual is inconsistent about the <Alt> modifier and C-x 8

which was filed against the emacs package, has been closed.

The explanation is attached below, along with your original report.
If you require more details, please reply to 39254@debbugs.gnu.org.

-- 
39254: http://debbugs.gnu.org/cgi/bugreport.cgi?bug=39254
GNU Bug Tracking System
Contact help-debbugs@gnu.org with problems