I've just tried downloading the
manual for Larrie and got a "File not downloaded. Potential security risk." message. If you expand it, it rambles about "file using and insecure connection" and so on. But at least it does allow you an option of downloading it anyway.
I use Firefox dev edition, ver 92.0b3 on Win10.
Just a heads up, in case you weren't aware of it already. Seems like yet another paranoid measure from Mozilla (or their parent company, google).