Composer is a dependency management tool for php, much like
cpan for perl. If you have read the tutorial about installing cpan, the architecture will be somewhat familiar. Composer, as a command line tool is the client that can fetch and update the php libraries we mark as needed, as well as the libraries these depend on, etc.
This is a companion discussion topic for the original entry at https://linuxconfig.org/how-to-install-composer-on-redhat-8