The mysterious extension "HEIC"

iCloud Photos on Windows

I sometimes use pictures and movies taken with my iPhone on this site where I use Windows to create pages. And recently, I noticed that some files with an unfamiliar extension "HEIC" appeared in the iCloud Photos. The file name of the newest QuickTime movie also has the word "- HEIC" at the end of it while keeping the extension MOV.

Because the corresponding file name to JPEG is attached, I thought it might be any additional information. But in fact, it was a new image compression format to replace JPEG. You can make a file size much smaller than JPEG with it.
As expected, Apple changes things dramatically as they adopted USB interface on iMac twenty years ago. This format will become the standard soon as well as USB. Is it a transitional measure that HEIC is paired with JPEG now?

Nonetheless, if I cannot open it on Windows from now, I will be in trouble, so I changed the format to 'compatibility priority' for iPhone's camera settings.
T.S

No change on Mac