The Introduction of the Monster Manual makes it clear several times that it is a book for DMs (MM, p. 4; emphasis mine):
This bestiary is for storytellers and world-builders. If you have ever thought about running a DUNGEONS & DRAGONS game for your friends, either a single night’s adventure or a long-running campaign, this tome contains page after page of inspiration.** […]
If you’re an experienced Dungeon Master (DM)**, a few of the monster write-ups might surprise you, for we’ve gone into the Monster Manuals of yore and discovered some long-lost factoids. […]
The best thing about being a DM is that you get to invent your own fantasy world and bring it to life, and nothing brings a D&D world to life more than the creatures that inhabit it. […]
The Monster Manual is one of three books that form the foundation of the DUNGEONS & DRAGONS game, the other two being the Player’s Handbook and the Dungeon Master’s Guide. The Monster Manual, like the Dungeon Master’s Guide, is a book for DMs.
However, it stops short of saying the Monster Manual is only for DMs, and does not specifically say that it should not be used by players.
Roll20, on the other hand, clearly made a decision to give players extensive access to information from the Monster Manual. Per the Roll20 wiki page for the Monster Manual:
Players can have direct access to the Monster Manual within the In-App Roll20 Compendium. You can share the Monster Manual with Compendium Sharing.
This is not a question about whether such information should be available to players – that is opinion-based and off-topic.
Rather, I am trying to understand:
Besides the statements in the MM itself, what do other official sources say about to what extent the information players have access to the information in the MM?
Did Roll20 ever explain their decision to provide players with full access to MM information?
While this is a list question, it is a bounded list – I am interested in official sources, and officially licensed sources.
It is not a ‘designer’s intent’ question in that I am not interested in opinion, interpretation, or speculation; I am just trying to track down relevant textual quotes about who has legitimate access to the MM information, and under what circumstances.