After flipping through all these pages I had some second thoughts about publishing an unwrapper, especially since David, Pete and Anton were a bit secretive about certain details such as the substitution table. Obviously, I decided to publish it nonetheless. Is this really harmful? There are already a couple of other 10g unwrappers available, such as:
A possible reason for the issue you are describing is that you have installed SQL Developer in a protected folder, e.g. under C:\Program Files. Installations have to be done as Administrator. See also -unwrapper-sqldev/blob/main/FAQ.md#i-cannot-install-any-extension-on-windows for more information.
aa06259810