I don’t know what a .webp file is but I don’t like it. They’re like a filthy prank version of the image/gif you’re looking for. They make you jump through all these hoops to find the original versions of the files that you can actually do anything with.
Edit: honestly I assumed it had something to do with Google protecting themselves from image piracy shit
Actually, just changing the file name doesn’t change the format. If it works, it’s because whatever place you uploaded to already supported webp.
If you download a webp file and you really want jpg, you need to actually convert it, not just slap .jpg on the end.
In that context: Websites may offer alternative image formats for the same image. They may offer jpg alongside webp. It’s just not easily discoverable by end users.