This could mean absolutely nothing. But on the Williams Green page on the Glastonbury website there is a video - and on the first frame there seems to be a cut out of Taylor Swift (and Daft Punk, amongst some others) with the caption - We've been going a while with secret shows, singalongs and general rambunctious behaviour.
https://www.glastonburyfestivals.co.uk/areas/williams-green/
Could this mean Tay Tay was planned to do a smaller secret set back in 2020 and this could be the one carried over into 2022?
I could be totally reaching here but thought I'd mention it in case