It’s harmless, won’t do anything on your site, and you can ignore it.
But here’s the explanation:
It is a bash script (has to be run on the command line), used by Travis-CI (a continuous integration service) to run unit tests for the plugin. This file is specified to be used inside of the .travis.yml file. WordPress itself never knows about or cares about or uses or can even do anything with these files.
But when I make a code change to the plugin, GitHub tells Travis-CI about the new changes, and Travis-CI grabs the new code, and then (on their servers) installs WordPress, installs the plugin (with the new code changes), and then runs a series of automated tests I have written to make sure that I don’t accidentally break something essential in the plugin with my code changes. And then it does this for: PHP 5.2, 5.3, 5.4, 5.5, and 5.5, for WordPress 3.9.3, 4.0.1, 4.1.1, and the latest WordPress, each in multisite mode and not, for a total of 40 different configuration combinations (imagine doing this by hand!). Then it lets me know if something went wrong.
