Namely
Squalane is an oil that has many affinities with the skin: it is one of the main components of sebum and the hydrolipidic film. It is also emollient and moisturizing. Vegetable squalane, which is sometimes called phytosqualane, generally comes from the unsaponifiable part of olive oil.
Controversies exist about it when it is of animal origin and extracted from shark liver: the shark is killed, its viscera are extracted and it is thrown back into the sea.
We hope that these practices are less and less common: make sure that the one used in your product is of plant origin. If it's not clear, call the brand to confirm. Squalane is produced by hydrogenation of squalene.