Why am I seeing this

Every ranked post can explain itself from its own ranking signals, and the same sheet is where you correct it.

Open the menu on any post in the For You feed and choose Why am I seeing this. The answer is computed from the signals that put the post in front of you. There is no extra request, and no model is involved.

The reasons a post can carry

Your post
You wrote it.
Following
You follow the author.
Your network
People you follow engaged with it.
Similar taste
Accounts whose taste resembles yours engaged with it.
Top quality
It scored highly on the quality signals.
Trending
It is gaining traction quickly right now.
Discover
It was included to widen your feed past the accounts you follow.
For you
It matches topics and creators you engage with.
New
It is recent, and recency is weighted up in your settings.

Correcting it

The same sheet carries the feedback controls. Show more counts +15, show less counts −20, and not interested counts −50, which is the strongest single signal in the system. Explicit feedback outweighs any amount of passive engagement.

Not interested is not the same as muting. It is a heavy negative weight on similar posts; a mute is an absolute filter. For an absolute answer, see Muting and filtering.