Simple patch fixing the bug
LogEventsList::getShowHideLinks uses Title::getPrefixedUrl, but the result is URL-encoded once again after it is passed through Skin::revDeleteLink. Title:getPrefixedDBkey should be used instead (c.f. PageHistory::historyLine).
This is probably not a problem for English-language wikis (since Special:Log does not have any escaped characters), but e.g. for a Czech-language wiki, that breaks the link (since Speciální:Log is double-encoded to Speci%25C3%25A1ln%25C3%25AD%3ALog).
Version: unspecified
Severity: normal
attachment LogEventsList.php.diff ignored as obsolete