What is bloat? [soliciting feedback]

I'm thinking of doing a thing, and was hoping for some feedback (and maybe it'll change my mind):

1. How do you define bloat in a browser?
2. What are some examples of it, and what browsers have it?

So far I'm thinking bloat includes...

* Extra software that typically is standalone, like an email client or RSS reader
* Things that are not widely wanted in a browser, and could be extensions, like an AI toolbar or a cryptocurrency wallet
* Advertisements built directly into the browser

Are PDF readers bloat?
How about LibreWolf's uBlock Origin?
And why/why not?
I've got some of my own reasoning in the list above, but I'm interested in others' thoughts.