Windows program files path names?

Maybe this can be a silly question but I don't figure out how to search in google why in some code I read, it is used to write this way: \\progra~1

What does ~ and 1 mean? I tried executing in Windows Run the same path but changing numbers and these are the results:

C:\progra~1 -> Opens Program Files
C:\progra~2 -> Opens Program Files(x86)
C:\progra~3 -> Opens ProgramData
C:\progra~4 -> Opens ProgramDevices, a folder I created in C:\

Why? Is this like a Match or something in the Folder names list?

For example a regex like "progra" and then to show the ~1 (First) match in some X order or ~2 (Second) ... etc?