When trying to open Robot Framework log (or report) I get an error in my browser:
"...
Opening Robot Framework log failed

Verify that you have JavaScript enabled in your browser.
Make sure you are using a modern enough browser. Firefox 3.5, IE 8, or equivalent is required, newer browsers are recommended.
Check are there messages in your browser's JavaScript error log. Please report the problem if you suspect you have encountered a bug.
..."

I am using Firefox v. 43 where javascript.enabled is true.

EDIT:

Per danielbeck in this comment, a possible solution to study is used in Cucumber-plugin: https://github.com/jenkinsci/cucumber-reports-plugin/pull/66/files