Meaning and relationship of the following terms : JSFL, JSAPI, CEP, AS3 panel, HTML5 panel

I googled for a while to develop an extension for Animate cc.
And I came across several terms: JSFL, JSAPI, CEP, AS3 panel, HTML5 panel

I'm confused.
JSFL and JSAPI look like terms that call the same object differently. It also appears to be building panels to overcome the limitations of vanilla JSFL, and AS3 or HTML5 are used for that.

Did i understand correctly?
I'm not sure.

As the first step in all of this journey, I'm studying JavaScript fundamentals these days, but I want to be clear about the meaning of the terms and their relationship.

Also, please let me know if you have a good study map for developing an extension of Animate cc at the end of 2019.

Thank you in advance.