I am a newbie trying to resurrect a Royal 10 that was "discovered" during a home remodel.  I am sure there is a
story but I don't know what it is.  I have a part "left over" after a partial disassembly for cleaning out the dirt, spiders,
crud, etc.  It appears to be, possibly, a "stencil release",  I tried downloading a photo to this site but would have to,
apparently, utilize a youtube account (a site I try to avoid).  For those that are familiar, assuming the part IS a
stencil release, what does it actually do.  There is a hole in the front plate above the margin release but how/what/??
it does is not clear.  Does it block the ribbon selector knob from going all the way to the right? 

A photo would be great and I have a couple.  But posting seems to be somewhat problematic (for me). 

Anyway, thank you !!