This information is not provided because it is too technical and changes on a regular basis. In order to use this feature, you will need to Google for recommended, best-practice client-side ciphers lists as of today's date. However, limiting the ciphers list to only strong, secure ciphers (as of today's date) will prevent your client from connecting to servers that only support older, weaker, or broken ciphers.
For example, I tried using the Mozilla
recommended modern, intermediate, and old cipher lists. These resulted in mIRC being unable to connect via SSL with at least 40% of the IRC servers that I tested.
As mentioned in a previous post, mIRC's current default ciphers list is:
However, this was last updated in 2014. If anyone has any suggested updates to this list, please let me know.