The page needs more explanation regarding the built-in deep linking parameters, such as placeID= (and the other undocumented parts). There are various other parameters that are undocumented (e.g. userID=[ID], to join this user’s server, if the player is allowed) which makes deep links very hard to work with (it’s basically a guessing game unless you track every deeplink you click on) and a black box situation with many functions unknown to the developer. Also, it is mentioned in this reply that you can encode Base64 string (though with some limitations?), this is also not mentioned in the documentation. There are two examples of undocumented behaviour that are not present on this page, which were figured out by purely guessing or by a Roblox Staff member’s response.
NOTE: well, I’ve found a list of all the supported parameters, but just not by roblox… oh well, time to play the guessing game to see what they do
Affected URL: Deep links | Documentation - Roblox Creator Hub