I know that it is kind a like basics, but as I learned, e in the ending is not pronouncing, but I've listened Stromae's song "formidable" where he actually pronounces 'e' on the ending. Which variant is correct?
In French, the letter e is often silent, such as at the end of a word, as in collège. There are several rules governing when e muet must be retained and when it must be deleted. Note however that retention or deletion also depends on the rapidity of speech, stylistic emphasis, and the type of consonants that precede or follow the e muet. See
Also « le e muet » is often not muet at all in songs, and almost never in poetry.