Add arbitraty HTML to project page

[Dzmitry Bahdanovich]

Hello,

I'm developing a new Jenkins plugin, which have to display a HTML table with some dynamic information about previous builds at Project page (please see http://prntscr.com/7s7eyd).

Currently my plugin consists of my custom job (derived from FreeStyleProject) and custom Build Step which can be applied only to my custom job. To display the html table at project page I changed a main.jelly file of the custom job to render my HTML table.

But now I get another requirement: I need to remove custom job and leave only the custom build step. This step need to be applicable to any freestyle project. And every freestyle project, containing the custom build step should display the HTML table. The problem is that I don't have access to main.jelly file of arbitrary job so I can't override it. 

Could you please give me a hint how to add HTML table to arbitraty freestyle project?

Thank you in advance,
Dzmitry

[Kanstantsin Shautsou]

Contribute Action from BuildStep#getProjectActions() with available jobMain.jelly that will be exposed to:  https://github.com/jenkinsci/jenkins/blob/master/core/src/main/resources/hudson/model/AbstractProject/main.jelly#L57-L60

Or, if it JobProperty, provide summary.jelly that will be exposed here https://github.com/jenkinsci/jenkins/blob/master/core/src/main/resources/hudson/model/Job/index.jelly#L43