How do the different ActivityPub platforms handle large posts that exceed their character limits? [duplicate]

What happens when an ActivityPub platform with a low character limit federates with a different ActivityPub platform that has a high character limit?

I'd like to configure my Mastodon instance with a very long toot length. I was thinking of setting this to something very large, such as 100,000 characters, such that the entire contents of my (sometimes very long) toots could be federated (note that a 100,000 character text post is probably smaller in bytes than many posts with 0 characters and 1 image)

My chief concern about federating article objects with such long contents is: how will other platforms handle it? Will they:

1. Display them in-full
2. Truncate them to their own "internal character limit".
3. Truncate them to some "external-content character limit"
4. Not display them at all.

Across the now-multitude of ActivityPub services on the Internet, how do they handle incoming federated article objects with hundreds of thousands (or millions?) of characters in their content field?