I can't find anything concrete online, but my assumption is that it has to do with the adventure / module design.
Consider a scenario where the party is going to go kill a lich, but first must delve into the lich's lair before they may fight.
"Prophet" being that the party is forearmed with the knowledge of what the final encounter will be - and perhaps some intelligence on the dungeon.
"Squeeze" where the party has encounters that drain their resources. Those grenades / fireballs are going to be handy for fighting the lich, but they're also useful for dealing with the lich's zombie army.
"Monster" where the party finally encounters the prophesied monster and fights the lich.
I've never heard this trope named this way, but it's how so many dungeons and adventures are designed. The party knows they have a particular fight coming up, and must carefully manage their resources because they won't be having that fight at full strength.
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