You can check out a similar site here, for example
https://academ.us/article/2202.04668/
If you click on the cross reference of figures and equations it will pop up a sticker showing the corresponding content, if that's what you mean.
For the most recent papers on arxiv, you can check out another site here
https://academ.us/article/2106.10522/
This one uses a different backend (pandoc), so slightly different pros and cons in rendering.