Is it possible to create Custom Fields, Screens, etc inside a Project Template?

I’m finishing a tutorial on how to create a Jira’s Project Template.
Link: https://developer.atlassian.com/server/jira/platform/creating-a-project-template/

In that Article, if you scroll down to my-project-template-config.json, we can create a new Issue Type. In the example below I’m adding a new issue type called “Findings”

            {
                "key": "issueType4",
                "name": "Findings",
                "description": "Findings from manual / automatic assertions.",
                "icon": "/images/icons/subtask_alternate.png",
                "workflow": "wf1"
            }

Now I would like to know the limitation of a Project Template. Can we also create Custom Fields Custom Fields Schemes, Screens, Screens Schemes, etc inside a Project Template? Perhaps from the same json file?

Screens are certainly possible, but not documented.
From the source code dependencySources/config/simple-issue-tracking.json is one example

Hi @mdoar I don’t see any simple-issue-tracking.json where did you get that?