I don't know, but my guess from their stated mid-term goals [1] would be that they're funding this themselves, in the hope of being hired for consultancy/feature development jobs on Servo once it gets used in small embedded devices, similar to how they get paid for contributing to other browser engines.
Edit: I also imagine most of the answer to "Who is funding Igalia?" in the FAQ of a similarly Igalia-led project, Wolvic, is relevant here [2]:
> Generally speaking, Igalia is funded by a wide variety clients. Some of our contracts allow or encourage us to discuss the work; others do not.
> Igalia works on a lot of things, from graphic drivers to multimedia, as well as the web platform. Igalia’s model expands the ability for investment into the web platform and web engines. We think that is not only good for businesses, developers, and users, but fundamentally useful to the long term health of the Web.
> Igalia itself re-invests in things we feel are important, but that we think under-served or else very, very interesting. Very often we are able to find good alignments with client work. Igalia is also the maintainer of a few official WebKit ports, including WPEWebkit, which powers millions of devices. We are able to do this and build a team around a diverse combination of investments, which in turn makes WebKit better and helps the larger web ecosystem remain healthier. Our ideas around XR are not dissimilar.
Edit: I also imagine most of the answer to "Who is funding Igalia?" in the FAQ of a similarly Igalia-led project, Wolvic, is relevant here [2]:
> Generally speaking, Igalia is funded by a wide variety clients. Some of our contracts allow or encourage us to discuss the work; others do not.
> Igalia works on a lot of things, from graphic drivers to multimedia, as well as the web platform. Igalia’s model expands the ability for investment into the web platform and web engines. We think that is not only good for businesses, developers, and users, but fundamentally useful to the long term health of the Web.
> Igalia itself re-invests in things we feel are important, but that we think under-served or else very, very interesting. Very often we are able to find good alignments with client work. Igalia is also the maintainer of a few official WebKit ports, including WPEWebkit, which powers millions of devices. We are able to do this and build a team around a diverse combination of investments, which in turn makes WebKit better and helps the larger web ecosystem remain healthier. Our ideas around XR are not dissimilar.
[1] https://people.igalia.com/mrego/servo/igalia-servo-tsc-2022/...
[2] https://wolvic.com/en/faq/#who-is-funding-igalia%3F