Trigger a downstream project on demand

[Versal Eszett]

Given the following situation

• main-job builds and tests a project
• installer-job copies artifacts from main-job, and packages them into an installer

installer-job is set as downstream project of main-job via Parameterized Trigger Plugin.

But the installer-job should only be triggered on-demand from main-job's build page.

It's possible to trigger the downstream job on the project page:

But it doesn't seem possible to trigger the build from a specific build page.

Is there any option to get such a trigger button on the build page?

Note: It's a freestyle project, not a pipeline one. So things like the Build Pipeline plugin don't help, unfortunately.

Thanks!