a public network was somehow able to read and flag the message
That did not happen - snapchat would refuse to connect to its server completely if the cert wasn’t recognized, so even with one of these awful MITM inspection gateways present (by itself unlikely anyway in an airport AP / outside of a corporate network, because they couldn’t deploy their custom CA to the clients) it would’ve been impossible.
This was obtained through snapchat itself providing the logs real time to GCHQ.
With the state of Javascript being what it is, you probably can chain syllables randomly and have a fair chance of the resulting word being the name of a temporarily-existing framework