When Leonbergers are shown in a FCI country they judged according to the FCI Leonberger Standard (no.145).

Non-FCI member countries cannot use the FCI standard because their kennel clubs want a national breed club to be responsible for the breed standards.
National Kennel clubs usually have their own requirements regarding the content of the breed standards.
When a Leonbergers are shown in a non-member country, they are judged according to that countries Leonberger Standard.
Of course, the non-FCI member clubs of the International Leonberger Union will always try to keep the breed standards as close as possible to the FCI standard.
However, due to the requirements of the kennel clubs there may sometimes be minor differences.

FCI Standard     Illustrated Stardard U.S.A.    Standard United Kingdom   Standard Canada