A corporate proxy, in the sense the IP answer uses, is the egress of a company's secure web gateway — the cloud service a business routes every employee's browsing through for filtering and inspection. Each employee reaches the Internet from the gateway's address in whichever of the provider's cities their office was steered to, so a whole company in Munich can appear to be a handful of addresses in Frankfurt, and the traffic is a workplace, not a home connection and not a bot.
What Spaw answers
is_corporate_proxy is true on an address inside the cloud enforcement node ranges Zscaler publishes for each of its clouds so that customers can allow-list them; corporate_proxy names the operator. The flag carries no risk weight, and like relay egress and a verified crawler it switches the datacenter weight off, because the gateway sits on infrastructure by design and its operator is known. connection_type reads corporate_proxy, and the cross-signal consistency check withholds its country comparisons for such an address, since the country is the gateway's.
What it does not mean
It says nothing about the company or the person behind the gateway, and a gateway address is shared by everyone routed through it, so a per-address decision reaches a whole office. Read it as "a workplace, located at the gateway", and stop there.