Mimicking the proof environment

I want to mimic the proof environment from the amsthm package.

I want something that has the same layout (margins, etc.) as the proof environment, but with the following changes:

1) Instead of beginning with Proof., I want it to begin with Proof outline.

2) I don't want a white box added at the end.

\documentclass{article}
\usepackage{amsthm}
\begin{document}
Here is introductory text.
\begin{proof}
Here is text in the proof.
\end{proof}
Here is concluding text.
\end{document}

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You can do this just by patching in a few optional commands to the proof environment itself.

\documentclass{article}
\usepackage{amsthm}
\newenvironment{proofoutline}
{\renewcommand\qedsymbol{}\proof[Proof outline]}
{\endproof}
\begin{document}

\begin{proofoutline}
This is not a proof.
\end{proofoutline}

\end{document}

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