So I tried:

aptitude install kdiff3

and got 100+ packages related to KDE.  A little too quick on the 'yes' I 
was...

Thankfully this awk command:

https://ubuntuforums.org/showthread.php?t=2133328

lets you 'undo' everything installed by mistake.

What would be the proper package to install to get the KDiff3 from TDE?  Well, 
I can find that on my own with an apt search I guess [1], so..

Really more relevent, Is there some sort of 'global' naming pattern to 
translate from what would be the KDE package name to the TDE package name?

Thanks All,
Michael

[1]
# apt-cache search kdiff3
kdiff3 - compares and merges 2 or 3 files or directories
kdiff3-doc - documentation for kdiff3
kdiff3-qt - compares and merges 2 or 3 files or directories -  Qt version
kdiff3-trinity - compares and merges 2 or 3 files or directories [Trinity]
kdiff3-trinity-doc - documentation for kdiff3 [Trinity]

Just add "-trinity"???  If so add that to the top of the Trinity Applications 
page, https://www.trinitydesktop.org/applications.php please !! :)