This post announcing the release of Bitcoin Core 0.20.0: https://lists.linuxfoundation.org/pipermail/bitcoin-core-dev/2020-June/000091.html
... shows a sig from key 9DEAE0DC7063249FB05474681E4AED62986CD25D
I have an old key for Wladimir J. van der Laan 01EA5486DE18A882D4C2684590C8019E36C2E964.
Please can anybody tell me how I'm supposed to be sure that 9DEAE0DC7063249FB05474681E4AED62986CD25D is indeed a legit key?
I would suggest you to test any key/s (when in doubt) with "PGP pathfinder & key statistics" using the following service. But to do that you need to have key/s of other people (sure, members of crypto community) to whom you trust, thus increasing your confidence in the checked key/s.