Not sure if there's a better source, but there is this:
https://www.postofficetrial.com/2021/03/project-sparrow-firs...
Looks like Arial to me.
Edit: Yes, it's Arial. Played with typing up a passage in Arial and adjusting using MS Word's justified text setting. I was able to get the right spacing etc. Here's an overlay with a image snip of the original document and my attempt (in red) overlayed. It looks almost identical.