There is a convention to have library symbols' name field contain the 
right prefix but "??" suffix instead of number. So a resistor symbol's 
initial name is R??, a capacitor's is C??, an opamp's U??, etc. I've 
followed this convention in the standard lib.
<p>
When you initially place them, this means you will get a lot of symbols 
that will be combined into the same component during compilation due to 
name match. This may cause attribute collisions (compilation errors), 
especially if you start assigning different values and footprints before 
actually naming your symbols.
<p>
To overcome this inconvenience, I've implemented an optional feature, on 
by default, which renames "?" ending symbols to autogenerated unique named 
symbols during compilation. Note: this code does _not_ change your 
drawing, the concrete model, it changes only the abstract model. So your 
symbols are still named R?? and C?? and so on, until you rename them.
<p>
It's a similar mechanism how unnamed nets are automatically named. There 
is a big difference tho: in case of networks, we have to name every 
network at the end of the day. In case of symbols if a symbol does not 
have a name attribute, that means you do not want it to show up in the 
output ("netlist"). So this feature does not _create_ a name attribute on 
symbols, it only transforms existing names if they are ending in one or 
more "?" characters, assuming these are "yet-to-be-named" symbols.
<p>
The feature can be disabled via the plugins/std_cschem/fix_unnamed_syms 
config node.