These spin-offs don't support smartcards.
Is this an indication that post-Mozilla1.5 versions of the browser and e-mail client will drop support for digital signature/e-mail/smartcards?
There are plenty of issues with security in the standalone versions of the e-mail client and browser.
Smartcard support is one of them. Nobody bothered to write a UI for them in Thunderbird or Firebird.
Another problem is that the security databases present in NSS are only multi-process safe for read-only use (as used in Netscape servers) but not for read/write. Nobody seems to have given any thought to this major problem, which basically means you can't share your cert and key databases between Firebird and Thunderbird if they are running at the same time.
Solving this problem involves using a new database format. The NSS team researched the issue of licensing other database code that didn't suffer from the single-process limitation, but none was found that would satisfy all licensing requirements - NPL/GPL/MPL. The only satisfactory databases we found were commercial. Unfortunately we didn't have the resources to write a brand new database, hence the situation we have today.
At this time, your best bet if you want good security support including smartcards is to stick with the monolithic Mozilla browser, which already has the PSM (Personal Security Manager) and will function correctly as a single process.
