We just recently started using ADRs (Architectural Decision Records). They are deliberately stored (in markdown) in the same repository as the source code for our SaaS business lives. If we can recover the source, chances are high that we can also recover the "why's". If we cannot do that, we are screwed anyways.
This. I encouraged my team to use a templated (standardized) ADR for any big decisions that don’t have an obvious answer or complete consensus and it had reduced the second guessing and relitigation of decisions to nearly zero. It also gave is a good snapshot of where we were when we made that call so historic decisions weren’t disparaged.
