The need for browsers to natively render mathematical text has been evident from the earliest days of the Web at CERN. Mathematical notations form a fundamental aspect of writing systems and are found in all civilizations. They have been instrumental throughout history for the diffusion and development of scientific and technical knowledge. MathML, the W3C standard for this, along with SVG, is one of only two other markup languages which are specially accounted for by the HTML specification and the HTML parser and are embeddable in HTML itself
However, MathML has a complex history. Its support in browsers thusfar has largely been achieved by contributions to the open source projects. Like SVG, its specifications came from a different (pre-HTML5/WPT) era. This meant that on the one hand they had a wide ecosystem of some support and tooling outside of browsers, and on the other they lacked important details and rigors explaining how they fit correctly and inter-operably into the web platform. As they lacked interest and involvement from implementer, the gaps between specs and browsers didn't improve. Eventually the Working Group disbanded.
In 2018 a group of people came together to attempt to correct this situation. Driven by implementation support and expertise from Igalia partially supported by some grant investments, there was a new effort to develop support in Chromium and identify a path to put things back on track. This resulted in a new specification, MathML-Core,
which provides the necessary details, a new shared test suite in Web Platform Tests and several changes (including partial support in Chromium behind a flag).
Perhaps the biggest hurdle for MathML in browsers has always been implementer investment. While it is very important, the fact that it is a significant feature which is less broadly appealing than many others and was in a complex state always makes it difficult for it to get the priority and attention it needs. However, relying exclusively on vendors for all development and maintenance investments isn't necessary, or perhaps even advisable. Just as Open Web Docs established a way to collectively ensure the health of MDN, MathML-Core support aims to establish a collective investment in the commons to fund these activities. MathML-Core support aims to make sure that MathML-Core has diversified implementation investements for all browsers that aren't subject to the complexities of prioritizing overall browser development budgets or held back by changing financial situations of any one company.
This collective intends to prioritize funding by first completing the two main items lacking in the Chromium implementation (tables and stretchy operators). Over the next year following, we will fund the the necessary maintenance and followup work that follows releases, and then continue the work to align implementations and improve interoperability.
Earlier work in getting this effort started and back on a standards track was generously funded by a grant from NISO/Sloan Foundation, Igalia, Pearson, APS Physics.