The Tag-Connect TC2030-CTX-STDC14 connects an ST STLINK-V3 debugger's 14-pin STDC14 connector to a 6-pad TC2030 footprint on your PCB, for SWD, SWO and reset on STM32 targets with no header fitted. This is the legged version; the no-legs version is the TC2030-CTX-NL-STDC14.
Which cable fits your debugger? See our Tag-Connect cable guide.