There is a file called "QuickKeys.txt" located within the Templates subdirectory that contains a list of key shortcuts :-)
At first sight, it seems that this file is regenerated everytime you start TFP15.
There is a location in the registry which contains the currently assigned shortkeys. I don't know if this can be modified.
Have a look at:
HKEY_CURRENT_USER\Software\Cadsoft\TFP15PRO\QuickKeys
The two entries are probably for the 2D and 3D views.
The first column (name) represents the resource ID of the strings in hexadecimal (explained below).
The data column contains the key shortcuts, again encoded in hexadecimal (0000041 is A, etc).
The resource IDs can be found inside Lang1001.dll by using a resource inspection tool.
For example, letter "L" points indirectly (0008673 in hex or 34419 in dec points to 00004C which is the hex code for the letter L) to the string "Inserts a Line by specifying 2 points &Line"
I'm writing a tool in Python to check this out in more detail.
Best regards,
eulores