The act of publishing generates files that are used by SSDT to determine what database changes to apply. What files are generated?
Navigate to your project's bin directory. Under that folder will either be a Release and/or a Debug folder. Depending on your configuration choice, you will have one or the other. The tutorial's configuration choice is shown below:
In this case, I have a Debug folder. Drilling into it, we see the following files:
The most interesting of these is the FutBol.dacpac file. Though it is a binary, it can be examined using archive programs such as WinZip and 7-Zip.
Opening this file with 7-Zip, I can see the following files embedded within the dacpac:
The postdeploy.sql contains the content of the Script.PostDeployment.sql we created earlier in this tutorial. The model.xml file contains the data model of our project. SSDT uses this information to compare against the target instance and to determine what changes are required.
While this is fun to look at, you shouldn't manually adjust anything in these files.