Learn Hardcore Afrikaans: Die kraak bevat plamuur.

Unlike English, Afrikaans does not have different forms like the for different genders, and unlike Dutch, it does not distinguish between articles like de and het.

Is kraak definitely a noun here, not a verb?

Yes, here kraak is a noun.

You can tell because:

it comes after the article die
it is acting as the subject of the sentence

So die kraak means the crack.

Afrikaans does also have words related to kraak as a verb in other contexts, but in this sentence the structure clearly shows it is a noun.

What does bevat mean, and why doesn’t it change?

bevat means contains.

Afrikaans verbs are much simpler than English verbs. In the present tense, the verb usually does not change depending on the subject.

For example:

Ek bevat would generally not be used naturally with this verb, but the form of the verb itself stays the same pattern-wise
Die kraak bevat
Die krake bevat

So unlike English, where you get contain vs contains, Afrikaans usually keeps one present-tense form.