Pijul is asking contributors to sign CLA
pijul.org
pijul.org
This has had 0 impact on contributions so far, since "signing" here just means including a patch as a dependency. In 100% of the cases so far.
Also, Libpijul is probably the last place you'd start if you wanted to contribute to Pijul. And since Pijul is GPL-2 and has no CLA, this means there's nothing hidden.