Safety is exactly one of the reasons why you'd want the complexity of software laid bare out in the open, rather than hidden as a black box of unknown size! Your own comment laments the clarity of two entire levers to control PTO versus an "opaque software stack" - why is it a forgone conclusion that that stack must be opaque?!
To address another objection of yours about unknown modifications, this too is an aspect where openness buttresses safety. Rather than blindly trusting that the software has not been modified (because such methods are unknown to you), the proper way to verify integrity is by being able to compare checksums or reflash, knowing there is no hidden state.
To address another objection of yours about unknown modifications, this too is an aspect where openness buttresses safety. Rather than blindly trusting that the software has not been modified (because such methods are unknown to you), the proper way to verify integrity is by being able to compare checksums or reflash, knowing there is no hidden state.