If you import the DemoSIte project in Eclipse then you will have access to the Broadleaf classes within Eclipse that you can open with CTRL + SHIFT + T ('Open Type'). Then you can set whatever breakpoints you want on these classes.
If you would like to try your hand at doing some modifications to the framework, if you pull down the latest version locally (currently the develop-5.2.x branch on GitHub) then you must make sure the version that you are targeting in your DemoSIte is the same that you have pulled down.
For instance, this is the current version that you will be compiling of Broadleaf if you pull down the develop-5.2.x branch from GitHub: https://github.com/BroadleafCommerce/Br ... pom.xml#L8
(at the time of writing this is 5.2.1-SNAPSHOT). If you were to compile this and do 'mvn clean install' to use this version of Broadleaf, it would build the 5.2.1-SNAPSHOT version.
IF you were to download the latest release of DemoSite, that version is currently targeting 5.2.0-GA and thus it will not use the version that you just compiled locally.
To remedy this, you should change the DemoSite version to 5.2.1-SNAPSHOT. I wouldn't recommend this but you can also check out the broadleaf-5.2.0-GA version of the Broadleaf framework to get the versions to match up.
The Broadleaf forums are being retired as a readonly archive of questions. For active discussions and questions, check out the broadleaf-commerce tag on Stack Overflow
which is actively monitored by the Broadleaf team.