There is an SMD part ident list on url h**p://www.marsport.demon.co.uk/smd/codeintro.htm (*=t) but unfortunately it does not list D10 but D11 and D13 which are Siliconics N-channel MOSFETs for switching. Maybe your type belongs to that family from Siliconics, it would be worth trying to look at https://www.vishay.com because they purchased Siliconics years ago.
Regrds, unkarc