I&#x27;m not sure what you mean by not understanding it. It is true that if you don&#x27;t have dependencies, &quot;cargo build&quot; will go get them, but if you don&#x27;t, then it shouldn&#x27;t. There have been some bugs that caused it to over-download, but those were bugs.<p><pre><code>  &gt; happily downloaded a random pre-built ELF binary to build itself.
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Yes, Cargo builds itself with Cargo, so you need to get a previous Cargo. The binary is very much not &#x27;random&#x27;.