Ticket created by ~omni on ~sircmpwn/aerc2
This is related to/inspired by the now closed #312.
Adding your custom RootCA to your hosts CA bundle may be a valid suggestion. However, even though the situation might be less horrible than a few years back, you may not want to trust all CAs in that bundle, nor remove all the others from the store, with the implications that that may have for other services and utilities.
Adding the option to select and trust a single root or intermediate CA would appeal to both those who add their own to their store as well as to the, probably larger, audience who want to narrow the number of strangers they put their trust to.