I am fairly familiar with the meanings of the word 'bolt', but I struggle to understand this sentence from a recent BBC article. If something is "bolted on to" something else, what does it mean? Please refer to a specific sense in the corresponding Lexico entry if possible (or another authoritative dictionary of your choosing).
"The COP itself is a consensus process, so it's a lowest common denominator. What we're seeing is other initiatives bolted on to the COP - there's real momentum."