[c3d]

DB48x certainly has a GitHub site with freely downloadable pieces of software that can run on the calculator. For instance here: https://github.com/c3d/db48x/tree/stable/library

Some of these include contributions from third parties.

The problem is that the law is written without a precise enough wording that would ensure that there is no risk whatsoever for me. And the penalty is stiff, something like $7500 per child using the software.

As for mandating age verification, it's unclear to me how you think that it's possible to deliver an API giving age bracket info (in the case of DB48x, the idiomatic way would be an RPL command that returns that info) without having a facility to enter age or date of birth or something like that. So yes, everyone who reads the text interprets it as mandating age verification.