I am not sure about the former(debuginfod support) but I believe LLDB does not currently have the support for debuginfod. From what I gather, there have been discussions around implementing custom symbol downloads and source file downloads using debuginfod but it is not present yet. Particularly, source file support with debuginfod needs to consider security concerns as it deals with sensitive source code information.
The changes required in LLDB to support debuginfod also need to change in the same areas as the submitted PR’s. Meanwhile that is implemented, we have custom module callback(RFC: Python callback for Target get module ) already implemented into LLDB. In addition, we wanted to have custom source file callback as a way for users to specify their own logic for fetching source files without worrying about security concerns.
Scripting symbol file plugin is new to me but sounds interesting. Does it allow for the same flexibility to override how users can fetch source files ?