The ornamental design for a plug for accessory-host interface, as illustrated and described.
FIG. 1 is a front perspective view of an ornamental design of a plug for an accessory host interface;
FIG. 2 is a front elevation view thereof;
FIG. 3 is a right side elevation view thereof;
FIG. 4 is a left side elevation view thereof;
FIG. 5 is a top plan view thereof; and,
FIG. 6 is a bottom plan view thereof.
The broken dashed lines showing the environment are for illustrative purposes and forms no part of the claimed design. Also shown in dashed lines are an optional lock-out key and an optional added pair of pogo pins, which form no part of the claimed design.