static-const-int-TAG_HEADER_SIZE-=-11;

This line of code declares a constant integer variable named "TAG_HEADER_SIZE" and initializes it with a value of 11. The "static" keyword means that the variable is only visible within the current file or scope. The "const" keyword means that the value of the variable cannot be changed once it has been initialized.

This variable is likely used in some code that deals with reading or writing data in a specific file format or network protocol, where the first 11 bytes of the data are reserved for a header that contains information about the rest of the data.