How to use the "web of trust" to verify QMSK (or, in my case, the Signal key)

Verifying signatures | Qubes OS says to use the pgp web of trust, but the wiki page it links to has no commands to run, no instructions, and the external links are not much help (since they just seem to point to https://www.research.att.com/~reiter/PathServer/ which is down). When I search for web of trust, https://www.mywot.com/ is what comes up, but I have a feeling that is not what is being referred to, because it is about integrity of sites, not keys.
Experimental PGP key path finder is up, but how do I verify that what it is saying is true? Any site can just say there is a path…

I’m thinking this is the same question, but how do I find the keys that are signed by the Qubes Master Signing Key (QMSK)? For instance, I’d like to find a trusted version of the Signal key (https://updates.signal.org/desktop/apt/keys.asc) while distrusting the infrastructure the whole time. I know there is this page to find who signs QMSK, but I don’t trust any of those (yet), so that doesn’t help. I have, however, verified my copy of the QMSK fingerprint, so I want to go the other way (whom QMSK signs).

Note that this is the response I got from that experimental path finder:

Looking for path from 0xDDFA1A3E36879494 to 0xD980A17457F6FB06. Find reverse path Get all keys listed

81916 nodes examined. 81916 elements in the hash
11 steps from 0xDDFA1A3E36879494 to 0xD980A17457F6FB06
0xDDFA1A3E36879494 (Qubes Master Signing Key) signs
0x063938BA42CFA724 (Marek Marczykowski-Górecki (Qubes OS signing key) marmarek@invisiblethingslab.com) signs
0xDB8FD31CCAD7D72C (Marek Marczykowski (marmarek) marmarek@invisiblethingslab.com) signs
0xFC1B547C8D8172C8 (Levente Polyak Z3r0.0x00@gmail.com) signs
0x4B043FCDB9444540 (Mattia Rizzolo mapreri@gmail.com) signs
0x5A09B4576DE8080E (Paride Legovini pl@ninthfloor.org) signs
0x086DC2A6D40B9D04 (Janos Farkas chexum+dev@gmail.com) signs
0x824D906CCA885078 (Carlos Y. Velez velez.carlos.y@gmail.com) signs
0x1EDF0DB99D8B7A84 (AMasterson1979@pm.me) signs
0xF5378C6B2B177925 (Daniel TePaske dtepaske@gmail.com) signs
0xB754EB6BA214CDDB (Daniel TePaske dtepaske+phone@gmail.com) signs
0xD980A17457F6FB06 (Open Whisper Systems support@whispersystems.org)

List of key ids in path:

0xDDFA1A3E36879494 0x063938BA42CFA724 0xDB8FD31CCAD7D72C 0xFC1B547C8D8172C8 0x4B043FCDB9444540 0x5A09B4576DE8080E 0x086DC2A6D40B9D04 0x824D906CCA885078 0x1EDF0DB99D8B7A84 0xF5378C6B2B177925 0xB754EB6BA214CDDB 0xD980A17457F6FB061 nodes examined. 81916 elements in the hash
Can’t find any further paths
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