$\Newextarrow{\xhookrightarrow}{10,10}{0x21AA}$
6.12
\begin{equation} \begin{gathered}\label{equation:cocartesian-fiberwise-localization} \xymatrix@R =50pt@C=50pt{ \operatorname{\mathcal{E}}\ar [rr]^{F} \ar [dr]^{U} & & \operatorname{\mathcal{E}}' \ar [dl]_{U'} \\ & \operatorname{\mathcal{C}}& } \end{gathered} \end{equation}