Memory Sections and VMA vs LMA
Every variable and every function in your firmware ends up in one of about six buckets, and which bucket it lands in is decided by two things: whether it is code or data, and whether its initial value is zero. That is nearly the whole rule. int counter; goes in .bss because its initial value is zero. int counter = 5; goes in .data because it is not. const int limit = 5; goes in .rodata because it never changes and can therefore stay in flash. Nobody chose those placements for your variable; the compiler applied that rule and emitted a section name.