"Steam Community Market Quick Buy" Google Chrome extension legal?

[Vetrarnott]

I want to buy some cheap items for recycling, but those items are immediately bought by other users. I found this Google Chrome extension which replaces the "Buy now" button by "Quick buy", and you dont have to click the agreement checkbox, saving some time and making a purchase immediately. But is it legal to use, or is it against the Steam TOS? I want to find it out prior to installing this extension.

https://chrome.google.com/webstore/detail/steam-community-market-qu/pbfjlhfadijipchkejgenbnnoebonckm

[ReBoot]

Since the TOS are there for a reason, its illegal.

[Vetrarnott]

Answer found:

STEAM® SUBSCRIBER AGREEMENT
...
4. ONLINE CONDUCT, CHEATING AND ILLEGAL BEHAVIOR
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You may not use Cheats, automation software (bots), mods, hacks, or any other unauthorized third-party software, to modify or automate any Subscription Marketplace process.
...
Ok, Valve, I won't use it).