In the past we've had a bit of trouble with bitcoin wallets in Debian
when security issues emerged. If this package makes it into Debian
stable, will you be able to provide security support for the version in
stable without upgrading to new upstream versions for the release
lifetime of stable?
Yes - apart from the listed email address in the package, there is also a community managed Telegram group at
https://t.me/SparrowWallet and of course the Github issues page, both linked from the application Help menu. All are actively monitored.
It's worth noting as well that Sparrow hasn't had a security issue in the now 2+ years since it was first released. It had been the subject of external code review and build reproducibility is regularly checked by external parties.