$\Newextarrow{\xhookrightarrow}{10,10}{0x21AA}$
6.11
\begin{equation} \begin{gathered}\label{equation:localization-and-categorical-pushout-easy} \xymatrix@R =50pt@C=50pt{ \operatorname{\mathcal{C}}_0 \ar [r]^{F_0} \ar [d]^-{T} & \operatorname{\mathcal{D}}_0 \ar [d] \\ \operatorname{\mathcal{C}}\ar [r]^{F} & \operatorname{\mathcal{D}}, } \end{gathered} \end{equation}