So, you come to a new job and join a channel that has been around for 2 years. Design decisions and discussions from 4 months ago with the old tech lead are there. Does weechat give you access to those logs?
No, not by default but if your organization uses IRC then it would be near guaranteed that whoever set up the IRC server will enable logging on all channels and then likely give you a web front end to it so you can easily read and search through all of the history.
In other words, yes, in any reasonable environment you would have access to everything ever said in any logged channel.
In other words, yes, in any reasonable environment you would have access to everything ever said in any logged channel.