It is not. It is an adjective. Popular culture has made it a colloquial verb for deeming a video as one's "favorite" but it is not corret English.
The verb appear can be a linking verb or an action verb.
Favorite can be used as a noun when it has an adjective in front of it such as the favorite or my favorite. The adjective favorite is based on the verb to favor.
It is a regular verb
"Had" is the past of the verb have, a form of the verb 'to be'.
The verb 'is' is a form of the verb 'to be', a being verb as opposed to an action verb. The verb 'is' also functions as an auxiliary (helper) verb. The verb 'is' also functions as a linking verb.
A linking verb.
A linking verb
It is an irregular verb.
The past tense of "to sing"; it can be intransitive (as in, "Jeremy sang last night") or transitive (as in "Jeremy sang his favorite song last night").
"Is" is the verb in this sentence.
It is to favour.
The verb appear can be a linking verb or an action verb.
change it first to: (Many people's favorite food is chocolate) so PEOPLE is the SUBJECTand since there is no proper verb, the VERB will be the helping verb IS
Favorite can be used as a noun when it has an adjective in front of it such as the favorite or my favorite. The adjective favorite is based on the verb to favor.
An auxiliary verb
the infinative
Is becomes a verb