1.) To find an engram to override, navigate to the mod folder on your computer and search for "engramentry".

2.) Add an entry like this to your game.ini file:
OverrideNamedEngramEntries=(EngramClassName="EngramEntry_XLWall_Adobe_C",EngramHidden=False,EngramPointsCost=0,EngramLevelRequirement=0,RemoveEngramPreReq=True)

For example: Scorched Earth Overrides[rb.gy]
Removes the vanilla Scorched Earth prerequisites from SS Scorched Earth items.

You can find a lot of information on what the options do with a simple google search.

The spawn codes spreadsheet contains a full list of engram names on the second tab[rb.gy]!