These are standard cells, the GATE_N means it is a latch (not edge triggered flop that uses a CLK gate input), it propagates the D input to Q when GATE_N is low (the _N means active low). RESET_B resets Q to 0 when low. The signal naming usually helps to understand the function. You can get the description in the pdk: ~/projects/foundry/skywater-pdk/libraries/sky130_fd_sc_hd/latest/cells/dlrbn/sky130_fd_sc_hd__dlrbn.functional.v