Sourcegraph PM here. Both Scala and Cobol are supported out of the box through search-based code intelligence (https://srcgr.ph/3xDPYcs). We don't currently support RPG and PL/1. We also offer precise code intelligence (https://srcgr.ph/3hBPnlT) that's powered by the LSIF protocol, this requires some setup and is currently available for Go(https://srcgr.ph/2U847Ac), Java(https://srcgr.ph/3r7quBT), TS/JS(https://srcgr.ph/3B57DMy) and C++). We have an easier path to supporting Scala in the future due to our Java indexing work, at the moment we don't have a concrete timeline for it.