Google Authenticator / OTP is used for 2 factor authentication by some websites, it is safer than sending a verification code by SMS and can be used offline.
Is it safe to install the testing repository? Do I need to configure some APT pinning if I only want to install the testing version of a specific app, like it is done when we are installing the testing repository on Debian stable?

PS: I know that Maemo 5 is not very active but this may change with Maemo Leste.