The page <https://help.libreoffice.org/Common/Comparing_Versions_of_a_Document> shows an outdated menu entry: It reads 1. … choose Edit - Compare Document. but the menu entry has been moved to Edit - Track Changes - Compare Document This error seem to be on all localized versions of this page, too (I checked a few). The LibreOffice build-in Help seems to be okay (checked German only). Sorry for not editing this in the wiki, I have the impression these are generated files anyway.
The wiki help is obsolete since release 6.0 and has been replaced by https://help.libreoffice.org . The referred page is now https://help.libreoffice.org/6.4/en-US/text/shared/guide/redlining_doccompare.html?DbPAR=SHARED#bm_id3154788 and has the correct menu path described. Thanks anyway for reporting. Wiki help is left online for legacy purposes (users still using old versions)