Our Joomla! extensions are all OpenSource and free of charge. Support is also free of charge. Nevertheless, we do have costs that need to be paid. This is done out of our own pocket. We have had a donation button on our website for some time now, which is actually used to make donations from time to time. The donation progress bar is intended to show how much support we have received and how much is still missing to cover the basic costs, such as hosting and services. The annual costs currently amount to 356€.
Thank you for your support!
KaTeX 1.3.0 is a maintenance release.
https://github.com/svanschu/Joomla-Tex-Tools/issues