The SDK documentation won't let me post this article right now, so I'm posting it here. Will get Tom to fix the site shortly :) This covers how to make the new .c2addon files supported in r120+.
-------------
The .c2addon file format allows plugin, behavior and effect developers to easily package their addon in to a single file. Users can then drag and drop the file in to the Construct 2 window to install it.
A .c2addon file is actually a zip file with a renamed extension. The zip file always contains *info.xml* in the root, and a subfolder called *files*. What goes in the *files* folder depends on whether you're publishing a plugin, behavior or effect.
#info.xml#
The info.xml file specifies metadata about your addon. It states whether the type is a plugin, behavior or effect, and has information like the name, version and author of the addon. It should be straightforward to fill out. Be sure to write documentation and add the link to the documentation to info.xml.
#Plugin and behavior files#
When distributing a plugin or behavior, the *files* subfolder needs to contain another subfolder. For example your folder structure in the zip would be:
info.xml
files\myplugin\common.js
files\myplugin\edittime.js
files\myplugin\PluginIcon.ico
files\myplugin\runtime.js
*myplugin* is the name of the plugin or behavior folder, as it should appear in the install directory. Construct 2 will simply copy and paste this entire folder, preserving the folder name.
#Effect files#
When distributing an effect, simply place the .fx file and .xml file for the effect in the *files* subfolder in the zip, for example:
info.xml
files\myeffect.fx
files\myeffect.xml
#Packaging#
Add all the files to a zip (right-click and 'Send to compressed (zipped) folder' in Windows Explorer). Be sure not to accidentally create a root level subfolder in the zip which itself contains info.xml - that will be rejected by Construct 2. Once zipped, rename the file so the extension is .c2addon rather than .zip. Test it by dragging and dropping the file in to the Construct 2 window. If you can install after the prompt successfully, your file is ready to distribute.