Does exactly what I wanted it and what it says to do. Two things that maybe are useful for others: 1. I wanted to call a JS function on close. So I added my stopVideos call (if it is there) to the frontend.js file of the plugin: {key:"closeModal",value:function(){ if(typeof stopVideos=='function'){stopVideos();} If there is any better way, let me now (same for 2). 2. The pink logo svg in the editor was way too huge for me. I don't know the reason, but to dodge it I wrote the following rule into the corresponding editor CSS file of my theme: .popup-preview svg {display: none;}

Lightweight block does exactly as advertised. Can activate by anchor link and a few other ways such as: page exit, timer, scroll location. Make sure to put it at the top of editor blocks, otherwise it does a few funky things when displaying.