In version 2.10b3, the help file about revision history refers to http://jabref.sourceforge.net/revisionhistory.php .
When clicking on this link, this page is not displayed.
The console shows "Could not find html-help for file 'revisionhistory.php'."
Note: save behavior in version 2.9.2
I got oppen the link and the bug is solved and closed.
Sorry, I had to be more specific: for revision history it does not work for French language.
With the English interface, same thing in the help "About bibtex", for the link "Recommended BibTeX Format" (at the bottom of the page).
Console message is "Could not find html-help for file '488'."