I will offer my opinion here, but this is an open question to the community and the definition of techbrobabble will likely evolve with the comm. All thoughts on what is, what is not, and what should be considered "techbrobabble" are welcome in this thread.

First: some things it is not:

• techbrobabble is not technobabble. Technobabble as employed by scifi writers is scientific or technical-sounding mumbo-jumbo, with widely varying degrees of correspondence to what I would call "correct technical jargon". Examples of technobabble that are not techbrobabble might be "reversing the polarity of the warp core", or "that's what things would be like if I'd invented the finglonger".
• techbrobabble is not merely technical jargon. Technical jargon has an important role in technical discussion, and it can feel exclusionary to those not intimate with the jargon of the field being discussed. Something like "load balancers are useful for horizontally scaling web services" is technical jargon, but it isn't techbrobabble.

I think techbrobabble is best described alongside its intent, e.g. "Technical jargon used in bad faith" or "The use of technical-sounding language to deceive or manipulate the audience". maybe a succinct definition would be "malicious technobabble".