This is a very simple program I have been working on for my personal use, but I might as well share it.
This takes the exported tsv files from the Pack File Manager so you need that tool first.
If you would like the Source code just send me a PM. Also if you have any trouble post here and I will help.
Features:
Ability to Search by Key or Value through all Records
Ability to Search by a Known Key, New ones can be added to the Catergories.txt file.
Ability to Merge any Two files, Records in the Second file will override the ones in the first file.
Ability to Save a file with Only the records you have changed in a File.
Ability to Merge the Changes of the file with another file.
Important:
Once you save a file in this editor, it will not open in excel correctly, but it will still reopen in the editor, and still be able to be imported back into the localization file, so don't worry if it does not open right.
See Attached Files for Download.