Developing Opera and other browser extensions in C#

[Philipp Schumann]

Hiya,

we're working on a product in C# which is to be used from the browser---that
is, under Windows, any of the three popular browsers (IE, Firefox, Opera).
Extending IE should be a breeze with some COM interop, Firefox seems to be
possible with lots of messing with XUL and XPCOM. However, I'm desperately
looking for information on how to extend Opera, not in terms of skins or
styles but in terms of browser add-on development.

Do you know any useful resources for browser extensibility in .NET in
general, but for Opera in particular?

Many thanks,
Phil