For the Preferential (New GUID) Firefox Extension to work with K-Meleon 74.0 and K-Meleon 75.0 Beta, download referential (New GUID) https://addons.cdn.mozilla.net/user-media/addons/713/preferential_new_guid_-0.8.2-fx+mz+zm+tb.xpi

Download Preferential hhttp://kmext.sourceforge.net/extensions/preferential.7z from K-Mwleon Extensions Central

The following steps create the extensions becasue the Firefox Extesnion does not contain chrome.manifest file

1 Create folder {e3a1bec3-1cc1-4d20-875b-a10587471a5e}

2. Extract preferential.7z\chrome\preferential.manifest into {e3a1bec3-1cc1-4d20-875b-a10587471a5e}

3.Rename preferential.manifest to chrome.manifest

4 Extract preferential_new_guid_-0.8.2-fx+mz+zm+tb.xpi
\install.js into {e3a1bec3-1cc1-4d20-875b-a10587471a5e}

5.Extract preferential_new_guid_-0.8.2-fx+mz+zm+tb.xpi\install..manifest into {e3a1bec3-1cc1-4d20-875b-a10587471a5e}

6. Extract preferential_new_guid_-0.8.2-fx+mz+zm+tb.xpi
\preferential.jar into {e3a1bec3-1cc1-4d20-875b-a10587471a5e}

7. Rezip files in {e3a1bec3-1cc1-4d20-875b-a10587471a5e}

7. Rename {e3a1bec3-1cc1-4d20-875b-a10587471a5e}.zip to {e3a1bec3-1cc1-4d20-875b-a10587471a5e}.xpi and copy it into extensons folder.

8. Last extract macros from Preferential http://kmext.sourceforge.net/extensions/preferential.7z into the K-Meleon Root Folder.