It goes back to Sparks of AGI [0] unless I am mistaken. Can recommend the talk, one that has stayed in the back of my mind since I first saw it two years ago. Personally, still have major reservations about throwing claims of intelligence or understanding around, but I do agree that SVG code generation can be a very effective source to get a quick and easy to present understanding of a models ability to output code with a rather open ended prompt that needs a high degree of coherence and were a lot of layers depend/build on each other.

Helps that these are eye catching (literally as the output is visual) and easy to grasp. Same reason a lot of hype is created around the web desktops.

[0] https://youtu.be/qbIk7-JPB2c?si=_TNRrxN-_5FOlfy5&t=1342