The current portable apps format specification describes a help.html file that is included in the "AppNamePortable" directory.
Exploring the file structure of the official apps, you see that this file is present for every app.
However, in order to access it, you need to browse to the folder for the app.
May I request that this be added to the context menu that you see when you right-click on an app shortcut, so that it can be opened directly from the menu?
The fact that they all are called "help.html" should help with coding this, n'est-ce pas?
It would be quite helpful, especially if there are special considerations for the portable version of the app.
I don't expect it to be in 2.0, but I hope that it could be there in some future incarnation of the menu.