One of the big things we get with used is the question of what previous owners may have added or changed!
This looks like a good bet it is not OEM but also a pretty good chance it is some form of battery disconnect??? It will take some looking to find what they tried to cut off.
Best is a switch with large contacts to carry the current and they put it in the negative (ground) cables of either the coach or chassis battery.
but it is not uncommon for it to be in the positive side when folks lack understanding!
One reason for saying it is not OEM is the drawings that do not show it and also seem to show the batteries are turned around from new! If I'm looking at the picture as being taken with the outer side at the bottom?
This drawing shows with the inside frame rail at the bottom!
Lots of info to help find what you have here:
https://www.winnebago.com/
Go to the owners tab and find lots of links to things like drawings and owners manuals that will help to sort things!
Electrical drawings for this part here:
https://www.winnebago.com/Files/File...995/114598.pdf
Click to get a better view!
As a help to get the best correct info on your specific RV, there should be a label next to the driver.
Owners manual here:
https://www.winnebago.com/Files/File.../95Sunrise.pdf
Info to "decode" the label is on page 0-4 but tons of help all through it! Part of the info needed may be due to the chassis is often one year newer than the RV as listed and sold. So to get chassis parts like brakes, we may need to use a different year than for RV parts!
Good luck on the chase!