Analogue of complex projective space, replacing GL1 with GLn

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$\mathbb{CP}^1$ can be formed from $\mathbb{C}^\times = \text{GL}_1$ by gluing $\mathbb{C}$ by itself along $\mathbb{C}^\times$, a pushout of $1/z,z : \mathbb{C}^\times \rightarrow \mathbb{C}$.

I am hoping that someone can help me to figure out a simpler form for the coequilizer $\text{Id}, \text{Inv} : \text{GL}_n(\mathbb{C}) \rightarrow \text{Mat}_n(\mathbb{C})$. Call this $\mathbb{CP}^{1,n}$.

Just as $\mathbb{C}^\times$-principal bundles correspond to both $\mathbb{C}$ and $\mathbb{CP}^1$ bundles, it would also be nice to know whether $\mathbb{CP}^{1,n}$-bundles correspond to principal $\text{GL}_n(\mathbb{C})$-bundles.