Where can I find the list of allowed attachments for Legacy HR Help Desk (Service Offering)?

I need to find out what attachments we are allowed to upload to Legacy HR Help Desk Service Requests (Service Offering/B2B Service version of Help Desk, not Redwood/NextGen). I looked through the Help Center and other documentation, but I cannot find this anywhere. I thought it was an admin profile option but when searching for %SVC%ATT% I do find a lot of attachment profile options, just not one that lists out the allowed attachment file extensions. I was almost certain I had seen this somewhere before but cannot locate it anymore. Thanks.