@huey1116
There isn't a simple answer to your question about "show more". When there's a difference in character limits in one Mastodon instance compared to another, it's the instance with the shorter limit that automatically generates that feature.

Functionally, in Mastodon, it's similar to the Content Warning feature (CW).

One can manually insert the command on Friendica instances by using BBCode format, but that doesn't always translate when a Friendica post is read by a Mastodon instance.