{make4ht} is a build system for TEX4ht, TEX to XML converter. It provides a command line tool that drives the conversion process. It also provides a library that can be used to create customized conversion tools. An example of such a tool is tex4ebook, a tool for conversion from TEX to ePub and other e-book formats.

Documentation at the link: https://texdoc.org/serve/make4ht/0.