LToolsD0i corresponds to the D0i function in LoopTools. The only difference is that the id should be entered as a string, e.g. "d0" instead of d0.
LToolsD0i
D0i
id
"d0"
d0
See ?LoopTools`D0i for further information regarding this LoopTools symbol.
?LoopTools`D0i
Overview.