When we publish an .apk from Unity, is it already signed with a keypair that we can use for publishing to the market? And if so, is this keypair kept so that we can publish updates to the same product later to the market? Or should we handle all of the signing ourselves and tell Unity not to sign the apk at all?
Under Player Settings for Android there is a submenu called Publishing Settings.
There you can create a keystore and a keyalias to sign your .apk during the build process. Be sure to keep the keystore you create (and of course memorize the passwords entered); it is needed when updating the application on the market.
If no key alias is set it will default to be signed with a debug key which is not allowed when publishing to the market (the web interface for publishing will complain if this is the case). The debug-signed .apk is only good for uploading to the device during development.
Sounds perfect. Thanks, erique!