The "Squash TA" label assembles several projects, physically present on Bitbucket's repositories:
The heart of Squash TA is the squash-ta-new-engine project. When we run a Squash TA ecosystem, the maven execution begins in the class org.squashtest.ta.maven.SquashTAMojo, which initiates the squash-ta-engine via interfaces declared in squash-ta-framework. This engine will then use the plugins that are required in the concerned tests.
The architecture of squash-ta-new-engine was completely refunded in the 1.5 version, to make it more modular. All the plugins have their own maven project.
Here is a general view of the physical architecture of squash-ta-new-engine: