Apache is a popular open source web server widely used on the internet for handling HTTP requests from web browsers and serving web pages. Apache handlers is a form of instructions to instruct the web server on how to handle/process certain type of files according to the file's extension type. For example, Apache web servr will know it needs to call Perl to process the file when the file has an extension of .pl. There are a list of default apache handlers already present in the web server, you can however alter the behavior of this by setting up customized apache handlers in your website.
NOTE: Making changes to the Apache handlers require good working knowledge of web server configuration, do not attempt to add/alter apache handlers if you are not sure of what it is as it may caused your website to be inaccesbile if it is not configured properly.
To setup Apache handler:
Click Apache handlers in your website hosting account control panel.
Enter the new file extension in Extension(s) text field. Be sure to include a . before the new file extension.
Enter the new additional Apache handler in the Handler field.
Click Add and the new apache handlers is added to the list.