Minecraft several hunger bars?

I often see youtubers that they have several hungers when they eat. But I did not find anything to do with this, so please answer me.

Call it a sample video

These are mostly client modifications. However, they themselves do not change the behavior, but only show how far the hunger bar is actually filled.

These are almost always modifications that are included on most major modpacks.

Otherwise partly on servers with PlugIns