There are a couple of posts about masterdata.xml that seem to indicate it's not a problem. See if either of these help.
For the 'main portal page' bit - maybe the developer wants to know the Start Page of the project, rather than the Default Topic? I'm not very familiar with CSH and webhelp, so I'm uncertain of the details the developer needs, but I wouldn't think you'd have to change anything as long as they have all the necessary details.
@Amebr: The links inside the other topic are broken.
The MasterData.xml is only present when you use merged webhelp. Anyway, I don't see why a developer wants it.
As for calling WebHelp, check out: http://www.grainge.org/pages/authoring/calling_webhelp/calling_webhelp.htm. Also, in your RoboHelp installation directory, there's a directory called 'CSH API'. That directory contains standard API's a developer can use to call your webhelp.
Nuts, they worked the other day. Plus I realised I linked to this thread, instead of the one I'd meant to.
Anyway, here are the two links from the MasterData.xml thread - I found them in the sidebar.
I can't remember which context sensitive topic I intended to link to, but I'll repost if I can find it.