Identifies the chart pattern we recognize as a Bull Flag, enters long, then exits 6 bars later. I do not claim this to be a good strategy, but a lot of people think the Bull Flag is (statistically) meaningful. This is a tool for you to test that claim. The exit after 6 bars is somewhat arbitrary, but it's basically "hold this position for a little bit to see if bull flags actually do anything."
I should disclose that the example I provided, /NQ on 15 minute charts, was cherry picked as one of the BEST examples where a bull flag appears to work (and 9 trades isn't a very big sample size). Don't want people to think bull flags are better than they actually are!