GCD of two polynomials with Euclide algorithm : Gcd

Gcd is the inert form of gcd. Gcd returns the gcd (greatest common divisor) of two polynomials (or of a list of polynomials or of a sequence of polynomials) without evaluation. It is used when Xcas is in Maple mode to compute gcd of polynomials with coefficients in $\mathbb {Z}$/p$\mathbb {Z}$ using Maple-like syntax.
Input in Xcas mode :

Gcd(x^3-1,x^2-1)

Output :

gcd(x^3-1,x^2-1)

Input in Maple mode :

Gcd(x^2+2*x,x^2+6*x+5) mod 5

Output :

1