With the sockets some had built in ceramic bead decoupling capacitors across the TTL power pins ( 8,16 or 7,14), so that you could either save 0.1in in spacing on the board for the capacitor, or add it in production if you found out at the last minute you really needed that extra 0.1uF ceramic, but there was either no time to respin the board, or you were not able to bodge in one as a line assembly mod at the rear, or just needed too many to make it work. IIRC they were available in assorted values, 100n, 470n, all in a dipped 50V leaded ceramic chip capacitor. You also got just a carrier socket with the IDC terminals inside, so you could use your own special value capacitor ( you probably could fit a 10uF 16V tantalum cap in there with care) in the socket, or any other component that would fit.