Not so much confusing as my own ignorance. My last pass through Polymer was two years (I think) ago and there's been a number of changes to the components specs

Not so much confusing as my own ignorance. My last pass through Polymer was two years (I think) ago and there's been a number of changes to the components specs that I've been ignoring. At the time I saw a lot of excellent examples/docs related to encapsulation and none related to content insertion. I'll take another look later this year.