Problems with relative pronouns

Why is 'what' a relative pronoun in this sentence: 'I know what I like'.

Why is 'whoever' a relative pronoun in this sentence: 'Whoever comes will be welcomed.'

I read that the definition of a relative pronoun is: 'Relative pronouns relate back to a noun or pronoun in a preceding clause, and they connect the two clauses.' I read elsewhere that: 'The relative pronoun introduces a subordinate clause.'

These definitions seem clear in the following examples (independent clauses = bold text, subordinate clauses = everything not highlighted):

The man who lives next door broke his leg.
[who refers back to man]


The refrigerator which had just been delivered needed cleaning.
[which refers back to refrigerator]

The book that I bought was on sale.
[that refers back to book]

He is a man in whom I have great confidence.
[whom refers to man]

I found a book whose pages were torn
[whose refers to book]

[Noego]

"I know what I like"

That's some really good questions. I'd be interesting to know this as well.

I'm raking my brain, but I can't seem to come up with an example where what is used as a relative pronoun.

In the above sentence I don't think "what" introduces a subordinate clause.

It's weird, Englishplus.com doesn't seem to consider "what" as relative pronoun:

"Relative Pronoun A relative pronoun "relates" a subordinate clause to the rest of the sentence. It may be found in adjective and noun clauses.
A relative pronoun is found only in sentences with more than one clause.
In modern English there are five relative pronouns: that, which, who, whom, and whose.
All but that can also be interrogative pronouns. That may also be a demonstrative pronoun.
In addition, these pronouns may take the suffixes -ever and -soever."


I checked the glossary on this website and came up with a similar answer:
"Relative pronouns, such as That, Who, Which, Whose and Whom can be used to introduce clauses in sentences"



None of them refer to "what" as a relative pronoun. I know in your example it's not an interrogative pronoun but I don't know what kind of pronoun it is.