Thanks for the info. I’m primarily a PHP developer, and I wanted to create a web-based solution where I could have a page that would display all of my projects as checkboxes, so I could select specific projects, then enter data in a field and submit to a POST call that would update the field in all selected projects. The return from the ajax call to /rest/api/3/project/search would be processed by PHP to extract project ID, etc. and generate a series of checkboxes.
I’m not sure how to accomplish something like that without using a browser, but I’d be interested in hearing your advice.