From version 1.8, Elements Checklist comes with a public Java API.
This API allows developers to read and write issue panel contents. It also allows to generate HTML from a panel content.
If you don't want to browse all the documentation, you can start here:
What can I do with this API?
Read a panel content
The API allows you to access a panel content in an issue. The panel content is composed of rows. Every rows itself contains types data, like numbers, dates, users, etc.
When reading a panel content, you have access to stored and calculated data. This includes calculate attributes and footers
Check the reference page about Reading a panel content
Write a panel content
The API allows you to write a panel content in an issue. You are allows to write all attribute types except calculate attributes.
Check the reference page about Writing a panel content
Get a panel in HTML
The Java API allows you to generate a HTML fragment from a panel. The code generates a HTML table, but you have control over the content style and formatting.
Check the reference page about Generating HTML
If you are developing an app, you can listen to Elements Checklist update events to be notified of any change.
Check the reference page about Listening to changes