Learn Dutch: Hoewel het bericht officieel is, gelooft niemand het. - Although the message is official, no one believes it.

This happens because of the V2 (verb second) rule. The entire first clause (Hoewel het bericht officieel is) acts as the first building block of the sentence. Therefore, the main verb (gelooft) must come immediately after the comma to take the second position, pushing the subject (niemand) behind it.

Why does the first clause end with the verb is?

The word hoewel (although) is a subordinating conjunction. It introduces a dependent clause, which forces the conjugated verb (is) to the very end of that clause.

This lesson covers volgens (according to). How would the sentence look if it started with 'According to the official message...'?

You would say: Volgens het officiële bericht gelooft niemand het. The phrase Volgens het officiële bericht takes up the first position in the sentence, so the verb gelooft still comes right after it to maintain the verb-second rule.

What does the het at the very end of the sentence refer to?

It refers back to het bericht (the message). Because bericht is a neuter noun (a het word), we must use the pronoun het for 'it'. If the noun had been a de word, you would normally use hem (him/it) as the direct object.