Inline footnotes or text blocks in Drupal 8

Here’s hoping someone can help…

I am looking for a way to make inline footnotes in Drupal 8.
There are two examples of what I mean:
1. lThe clickable words on a page like http://www.vulture.com/2018/02/quincy-jones-in-conversation.html (search for “his father told him he was ugly and abused him” )

2. the infobox on https://digitaal.scp.nl/mediatijd/bezit_van_media-apparaten/ (Click on the ‘+’ after ” Mediabezit- en gebruik sluiten aan bij behoeften van mensen ” )

I’m wondering if there is a module that facilitates something like these, preferably using existing modules or styles that integrate in the CKEditor.

Any advice highly appreciated!

Drupal version: 


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