Variable capacitor notation with a division sign (e.g. 2÷10p)
By Occam's razor, I would interpret the markings as the range of capacitance for the trimmers, and that it's a regional or idiosyncratic use of ÷ rather than ~ or -. 

This is confirmed by the text on the website- for example here. 


  Capacitive trimmers (Philips foil type, 7.5mm diameter with three leads) in the 106MHz and 213MHz bandpass filters are increased to 5-40pF (violet body), while the trimmers in the output stage at 425MHz are increased to 4-20pF (green body). 


Mechanical engineers sometimes indicate ranges by putting one number above the other, separated by a horizontal line, which, of course, is what ÷ is shorthand for.