Those two levers control the rear hydraulic ports. This ports are used on things like an hydraulic top link, dump trailer, a log splitter that hooks to the tractor hydraulic system and a lot more alternatives.
One of the levers has spring to return, which means the lever will return to center/neutral once you let it go. Let's say you have an hydraulic top link, you move the lever back or forth to adjust the top link length. Move one way, extends the cylinder. Move the other way, retract the cylinder.
The second lever has a detent. Meaning it stays in whatever position you let it go. This is used to power constant flow attachments. For instance, let's say you have a log splitter that connects to the tractor hydraulic system. You put the lever either forward or backwards and it is feeding the log splitter constantly, so you don't have to hold the lever like the other one.
When not in use, make sure this lever in the middle position or the 3 pt won't work and may cause damage to the hydraulic pump in the long term.
Here is an example on my F36. I'm using this hydraulic ports, also called remotes, to control the side shift on my tiller. Note the hoses going to the quick connects.
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