By setting up a gateway connection and then looking at the journal records I tracked down this global subtree:

%SYS>d ^%G
 
For help on global specifications DO HELP^%G
Global ^%SYS("sql","ODBCCONNECTION"
^%SYS("sql","ODBCCONNECTION","DATA")=1
^%SYS("sql","ODBCCONNECTION","DATA",1)=$lb("","ENS171 Samples","YJM","_system","HnBuSSuEERERntcVPGsUMQ==",0,0,"","","","",0,"",0,0,1,0,1,0,"",0)
^%SYS("sql","ODBCCONNECTION","INDEX","NameIndex"," YJM",1)=""
 
Global ^
 
%SYS>

The password (see yellow highlight) isn't stored in plaintext.

As well as our RE/* tools please also consider Yuzinji.

In addition to the main UI that is illustrated in the short video here, the output from Yuzinji can also be browsed in a web app. An example is available at http://demo.georgejames.com:8080/s101g/tracker/home.html where you can get some insights into how a couple of codebases have changed over time. One comes from the InterSystems SAMPLES namespace, and the other is from [@Eduard Lebedyuk]'s RESTForms project.

Following up one of Ben's points, if you're using a shared DEV namespace you can use a server-side source code management tool such as our Deltanji. This also gives you the option of using Atelier and Studio side-by-side, which is handy if you have a team of developers who may need to migrate to Atelier at different speeds, or if you deal with code components that Atelier doesn't yet handle satisfactorily. Also, Deltanji handles the migration of code from one environment to another (e.g. DEV -> TEST -> PROD). Using a client-side source control provider such as Git you'll need to put some other tooling in place to handle that.

Ideally the responses by Jenny Ames and [@Matt Spielman] would have been posted in the "Your Answer" area of DC rather that using the "Add new comment" link. That way  the OP, [@Conor Browne], could accept one of the answers by clicking on the grey checkmark at the top of the answer to turn it green. Doing this helps with DC housekeeping by removing the question from the "unanswered" list.

If Jenny and/or Matthew were to re-post their responses using the "Your Answer" field then Conor will be able to credit one of them with answering his question. Even them posting "See my answer in comments above" would be sufficient to give Conor somewhere to set a checkmark.

Alternatively Conor could either accept my answer (though it's not actually answering his question), or he could post an answer of his own, then accept it.