Open BLOG File
The BLOG extension, itself, is not a file extension, it is basically a generic top-level domain name or gTLD in the Internet Domain Name System.
The BLOG domain extension was created and added in 2016, and is intended to be used for blogs.
Anyone can sign up for a BLOG domain name, in some cases they are free, however, most of the time, it comes at a price.
Ideally, this extension should be used for the purposes for which it was created, that is, to host a BLOG there, it is not recommended to host another type of page.
Currently, anyone can purchase a BLOG domain from a variety of domain registrars, however it is important to know that there are some restrictions regarding brand names.