They act similar to delay and line objects, but when they're in the middle of a delay or a ramp, the message "pause" will act as a toggle between pausing and resuming.
The delay object, delp, has two additional outlets. The remaining time passes through the 2nd outlet whenever a pause occurs, and the toggle's current state passes through the 3rd outlet.
These objects all use timers to calculate their remaining time and ramp state, which means that linp will be precise regardless of what its time grain is set to. On the other hand, it also means that linp~ will sound inaccurate if there's any discrepancy between your audio server's sample rate and pd's sample rate because discrepancies of that kind, in general, result in the audio's timing being either too fast or too slow in relation to Pd's system timing.
Included is an example where these objects help with playback control, with linp displaying the remaining time, linp~ handling the fade-out effect, and delp triggering the fade-out and end of playback.