I'm aware of bunkers and of that lib. I've already seen that mysterious lib's button floating around on some webapps ^^.
Spring Browser is good and very similar but I think I can bring new ideas to the table that could work better, I hope.
There are some problems when trying to rehost web clients like api calls that won't work from different domains or blocked iframe loading.
For now I think if devs depend on my lib or on custom api calls to handle relay connection it may centralize things or be one more thing for them to learn. Though I definitely want to help handle things like user relay migration (copying events) that would be too much for every app to code and something the user shouldn't suffer with.
Thx for the ideas. I've added some extra explanations to the bottom of the campaign page.