Hi when visiting https://tools.wmflabs.org/extreg-wos/ it brings up a error saying tool does not exist but it was only working a few days ago.
Topic on Project:Village Pump
The page says that Legoktm is the maintainer, plus this does not look MediaWiki related so Project:Current issues might be a more appropriate place to bring this up.
You should ask the maintainer (@Legoktm:), if he can fix the problem :) I'll move this to Project:Current_issues for now :)