The oam file is just a zip file which you can extract, modify and re-zip it again.
So, do the below steps: First create a copy of original and work on that copy as follow
1. Rename the X.oam file to X.zip
2. Unzip it.
3. Modify the _edge.js file where you remove the "use strict";
4. Zip it again.
5. Rename it back with extension .oam
And you are done.
hth,
Vivekuma