Only by re-coding the Extension ie unpacking it, finding all of the relevant references, removing them, re-writing any effected logic within the scripts, then (optionally) repacking the Extension.
Of course, if you do this then you'll have to do it again each time the Extension is updated.
If you do decide to go ahead and modify an Extension (anyone's, not just mine) its common courtesy to follow any copyright included with the original Extension and, at the very least, include an acknowledgement to the original author.
As a note each XML and Lua File in each of my Extensions has this copyright notice in it:
I do NOT give permission for any of my code in any of my Extensions to be modified in any way, except for personal use by the individual performing the modification - that is, if you want to modify my code you can, but only YOU are allowed to use the resulting modified code; it MUST NOT be given to anyone else - in other words, follow the spirit of the copyright as well as the letter.Code:© Copyright Matthew James BLACK 2005-14 except where explicitly stated otherwise.
Fantasy Grounds is Copyright © 2004-2013 SmiteWorks USA LLC.
Copyright to other material within this Manuscript may be held by other Individuals and/or Entities.
Nothing in or from this File in printed, electronic and/or any other form may be used, copied,
transmitted or otherwise manipulated in ANY way without the explicit written consent of Matthew
James BLACK or, where applicable, any and all other Copyright holders.
Also, I won't/can't support any of my Extensions that have been modified by someone else - I'll do what I can to help, but if you do such a thing you do it under this understanding.
So, with all of that in mind, is what you want really worth it? The offending tab takes up very little screen real-estate, isn't it easier to just ignore it? :)
Or have I missed the point entirely?
Cheers

