I just want to make sure we are understanding your request. You want to populate a variable with the ID of an extension when the extension runs and send that extension number to a tag vendor?
What if multiple extensions run for a single tag? Do you want a comma separated list of extension IDs or just the ID of the last extension that ran?
Maybe a use case would also help us know the correct way to advise.
I can give a temporary answer below.
Without a use case I would suggest simply hardcoding this ID value via Set Data Values Extension or if the extension you want the ID from is a JS Code extension add another line that sets it.
If using a Set Data Values Extension (with an ID of 1) and this is the ID you want you can just add another line to the Set rows:
Set: "extension_id" To: Text -> "1" (No Quotes)
This will set extension_id to "1" and you can map "extension_id" to the necessary tag.
If you only want this ID set when a different extension runs, you can add a condition to this extension that checks for the output of the previous extension.
If in a JS Code extension you can simply add:
b.extension_id = "ID of Extension";
Replace "ID of Extension" with the actual ID of the JS Code extension. This will only get set if the JS Code extension runs and again you can map "extension_id" to the necessary tag.
Thank you Jared. I think the solution with simply adding another line with the text value for the extensions we need will do perfect. We are only looking to use this for troubleshooting purposes. We have multiple teams, and sometimes it's difficult to find the extension another person used if the naming isn't concise.