  The gravitational form factors (GFFs) of a hadron encode fundamental aspects
of its structure, including its shape and size as defined from e.g., its energy
density. This work presents a determination of the flavor decomposition of the
GFFs of the proton from lattice QCD, in the kinematic region $0\leq -t\leq
2~\text{GeV}^2$. The decomposition into up-, down-, strange-quark, and gluon
contributions provides first-principles constraints on the role of each
constituent in generating key proton structure observables, such as its
mechanical radius, mass radius, and $D$-term.
