For me, space+f is a "fuzzy search", a filter to find by filename. You can omit some characters, e.g. `pack/back/conf` would show `packages/backend/config.z`.

I have muscle memory now, so I'd have to open the editor to confirm it. There is also another mode, that works a bit like grep I think? I haven't used it but seems that you can look for matches in file content.