back seat
1 seat at the back of a car, etc 後座（位于汽车等後部的座位）.
2 (idm 习语) a ,back-seat `driver (derog 贬) passenger in a car who gives unwanted advice to the driver 对司机胡乱指点的乘客.
take a back seat (fig 比喻) behave as if one were unimportant; take a less prominent part in sth 装扮成不重要的角色; 在某事物中起较次要的作用.
后面这个习语，就是一个隐喻，符合指指点点的乘客。
idc_whitepaper_0101.pdf这里的这个含义是说，这个互操作问题，也会占有一席之地，虽然可能从功能使用上来说不重要。
In addition, the introduction of a “standard” implies that interoperability issues take a back seat.