Comment 32 for bug 1741074

One suggestion discussed in https://forum.snapcraft.io/t/allow-classic-confinement-for-postman-agent/19228 is to use a content interface to allow third-party snaps to write to ~/snap/chromium/common/chromium/NativeMessagingHosts/. Whether it’s a good idea from a security perspective is open for discussion, and it wouldn't solve all the problems discussed here, but it could be part of the solution to enable third-party native host connectors.