Attach HTML file to build report, it won't open in browser

I'm generating an HTML file during my build and attaching it to my build results. When I open the file from the downloads page it opens in a plain text editor instead of an HTML browser (plain text editor is NOT my default for .html files)

How can I get the file to open in a browser?

build snippet (removed tags for forum code):
artifactFilePublisher repositoryAddress="${repositoryAddress}"
userId="${jazz.user.id}"
password="${jazz.user.passwd}"
buildResultUUID="${buildResultUUID}"
contentType="text/html"
failOnError="false"
verbose="true"
filePath="${file.path}"
label="${file.description}"

on the build report the file shows text/html and UTF-8