How to save in .cache

hii everyone
i see a site where i found some link like with the extension .CACHE

& that is a complete page file names are like this 0c738f6ac15da0f4c558a151fdc4935a.cache

did they are saving in cache file instead of databse ?
if yes how is this possible ?

Read this article: Cache it! Solve PHP Performance Problems

well here is online streaming site this is cache url
that’s url which is contain on the code of their player area code… what can be the benefit of this type of cache & how can we generate

The article listed by Ernie1 walks you through how to do this.