The actual functionalities are called commands in ProFramework. Commands are usually started by a function. Commands are handled by the so-called Command Controller. With the help of the Command Controller, the actual logic can be split into several steps, which on the one hand increases the clarity, but at the same time is also a central prerequisite so that in different interface technologies a synchronous communication between the application server and the user interface can take place during processing. The command controller manages all data of a command and provides various functionalities to simplify the implementation.
There is a very detailed documentation of the Command Controller:
https://api.pronovia.ch/_pch_cl_cfw_ctrl_command.html
A list of all existing commands is available in ProFramework Customizing under Extensions → Application → Commands (display only). This also shows which steps are executed in which order and which data (parameters) are used in the command.
The list of commands also shows the origin of the command. The originators of commands usually also provide the corresponding commands as constants, which are ideally also used when implementing extensions.
By an extension with the help of the BAdI /PCH/CFW_CTRL_COMMAND of the extension spot /PCH/CFW_APPLICATION a command can be changed specifically. The extension possibilities are very diverse, but at the same time complex and require a deeper understanding of how this controller works.