The C28x compiler manual (SPRU514Y) in sub-chapter 7.1.1 Sections, states ...

The .econst section contains ... the declaration and initialization of global and static variables

Compile this example (for COFF ABI) to see this is incorrect ...

/* In .ebss, with initialization entry in .cinit */
int not_const_initialized = 10;

/* In .econst */
const int const_initialized = 20;

For a variable to go in .econst, the const keyword must be used.