Google is not done open-sourcing internal tools and this last one is yet another one, thankfully, where open-sourcing doesn't mean abandonment. The tool, dubbed, Ashier, is aimed at a very small niche, the people that need to automate terminal interactions.
That is to say, people who habitually run command line programs and scripts that require user input at various points in their progress.
System and network administrators would benefit the most from it, but it's also useful for programmers, researchers and anyone you can think of that regularly uses the command line.
"Ashier offers several advantages over traditional tools (such as expect): a template language that replaces regular expressions in many situations, support for nested multiline textual data parsing, and the ability to integrate with response logic implemented in any language," Google's Chuan-kai Lin, from the Site Reliability Engineering Team, wrote
The fact that the tool comes from Google's reliability team should give you an idea of how it's used internally and what's its main goal.