Andrew,
Unfortunately in AGOL WAB you do not have access to modify code that would allow you to develop the portion to add a popup link that would append the coordinates to the url of a link. WAB by default does have a center url parameter though:
But using the WAB (not AGOL) I could likely have some event listener to accomplish something of this sort, right? Any insight there?
I see https://community.esri.com/message/705716-passing-xy-coordinates-in-agol-or-agol-wab-to-outlink-url is a dupe of this conversation. Probably is best to have it as a new conversation, but if Robert (who would be the expert) answers is here, you might just want to delete the other....or include a link to the answer here and mark "assumed answered"
just an fyi, lots of good tips (including in comments) on posting to geonet https://community.esri.com/community/help-and-feedback/blog/2016/08/15/community-news-and-tips-how-t...
Andrew,
Yes Using WAB Developer edition will give you the ability to customize code and do exactly what you are after.