Pretty ancient stuff to bring up, especially in this context. Here's the last denial I recall by one of the people accused of planting backdoors in OpenBSD. Note the date.
It appears that there is a continuous audit of source code. So, even if a malicious hole was planted, it ought to be discovered in the years of repeated auditing. Cheers to OpenBSD!
https://www.itworld.com/article/2744922/open-source-tools/op...