In Tools > Customize... > Keyboard tab, the key names Prior and Next are used.  

Those are the X keysym names.  I looked at [1] and found that (a) many of the photographed keyboards, even some from non-English-speaking areas, used some variation of PgUp or PgDn instead of Prior and Next, and (b) none of the photographed keyboards seemed to use Prior and Next.  

Knowing that LO is derived from code written by the former Sun Microsystems, which sold keyboards with a proprietary layout, I even looked at a photo of a Sun keyboard on eBay and found that those keys are of the PageUp/PageDown variety.  

Can the strings "Prior" and "Next" be changed to "PgUp" and "PgDn" so that most users can more easily understand those entries in the Customize dialog?  

[1] http://matadornetwork.com/abroad/the-ultimate-guide-to-computer-keyboards-around-the-world/