Describe the bug:
In the latest servo run with --pref layout.grid.enabled content in the form of either normal text:
https://podcastbingo.glitch.me/ai.html
CSS used: grid-template: repeat(5, 1fr) / repeat(5, 1fr);

or emojis
https://emojicons.glitch.me/
CSS used: grid-template: repeat(18, 1fr) / repeat(2, 1fr);

are not populated into the LABEL elements.

To Reproduce:
Visit the pages linked above.

Screenshots:

Platform:
Linux Mint, laptop.

Discussion:
In the case of the normal text it may be that the function used to randomise which square on the bingo card to populate is using JS that Servo has yet to support:
self.crypto.getRandomValues()
I doubt it's the population method itself which just sets .textContent of the inner B element.
from https://podcastbingo.glitch.me/script.js

In the case of the emojis it may be that Servo is relying on the Linux Mint platform to provide the emojis and it isn't, or that the CSS used to populate the label elements is not yet supported in Servo:
input[name="c"] + label::before{content:attr(for);will-change:content}
from https://emojicons.glitch.me/style.css