Well each workbook should be setting its variables at the beginning of the workbook that may be sensitive like sas tokens or other api keys. Each workbook should just grab data, manipulate it, and upsert it to an existing table. The tables should then have group permissions for each developer use-case to control access to data and abilities to write new data... if you work backwards from a list of sensitive keys you could certainly export all your workbooks and search through them programmatically... but definitely have devs use the markdown cells to title sections and the ability to collapse different logic portions. As I mentioned, it should be clear in the beginning of the workbook if possible. In addition you could make it practice to use widgets and have the user input the api keys manually (which can be input in the beginning of a workflow and inherited to every other eorkbook with the same widget variable... let me know what you think. Your devs should know everything about the code though and document how it all works with this sensitive secrets to reference...