Pragmas can be used to hide program warnings when certain checks like extended program checks applied to the program/code lines.
The program- ABAP_SLIN_PRAGMAS lists all the pragmas which are available in the system and when can be applied.
Lets check a simple scenario. In a global class method- a variable is just declared but not used then. Then when extended program checks applied on the class, it shows a warning stating that- the variable is not used and also proposes the pragma name which can be used to skip the warning.
Select the highlighted line.
The system shows the cause of the warning and also provides suggestion how to deactivate using certain pragma.
Apply the pragma.
Check and now the warning is gone but the tool is smart enough that display the statistics of hidden errors/warnings.