There are a lot of instances of the following error in the Logstash Fatal Monitor:
Unrecognized value for parameter "action": wbgetitems.
#0 /srv/mediawiki/php-1.32.0-wmf.5/includes/api/ApiBase.php(1973): ApiUsageException::newWithMessage(ApiMain, array, string, NULL, NULL)
#1 /srv/mediawiki/php-1.32.0-wmf.5/includes/api/ApiBase.php(1544): ApiBase->dieWithError(array, string)
#2 /srv/mediawiki/php-1.32.0-wmf.5/includes/api/ApiBase.php(1261): ApiBase->parseMultiValue(string, string, boolean, array, NULL, integer, integer)
#3 /srv/mediawiki/php-1.32.0-wmf.5/includes/api/ApiBase.php(783): ApiBase->getParameterFromSettings(string, array, boolean)
#4 /srv/mediawiki/php-1.32.0-wmf.5/includes/api/ApiBase.php(855): ApiBase->extractRequestParams(boolean)
#5 /srv/mediawiki/php-1.32.0-wmf.5/includes/api/ApiMain.php(676): ApiBase->getParameter(string)
#6 /srv/mediawiki/php-1.32.0-wmf.5/includes/api/ApiMain.php(516): ApiMain->handleCORS()
#7 /srv/mediawiki/php-1.32.0-wmf.5/includes/api/ApiMain.php(506): ApiMain->executeActionWithErrorHandling()
#8 /srv/mediawiki/php-1.32.0-wmf.5/api.php(83): ApiMain->execute()
#9 /srv/mediawiki/w/api.php(3): include(string)
#10 {main}This looks like a perfectly innocuous user error (the API action is actually called wbgetentities), so it probably shouldn’t clutter the fatalmonitor dashboard.
(This isn’t specific to this API action, by the way – there are also less frequent log errors for a “history” action.)