You're hinting at the underlying problem with the quote. "Asset" in the quote reads, at least to me, in the financial or accounting meaning of the term. "Liability" reads, again to me, in the sense of potential risk rather than the financial meaning. Its apples and oranges.
Liability is also an economic term. As in, "The bank's assets (debt) are my liability, and my assets (house) are the bank's liability."
I don't think it's a wrong quote. Code's behavior is the asset, and code's source is the liability. You want to achieve maximum functionality for minimal source code investment.
Sorry, my point wasn't that liability doesn't have a meaning in finance. My read of the quote is that it uses liability in the sense of risk not debt on a balance sheet.
I could always be wrong though, that was just my interpretation of it. I don't get how code could be a liability in the financial sense, but I do get how every line of code risks bugs and other issues.
Tech debt is not part of a financial account or disclosure though. Yes those are forms of debt, no they aren't financial debts or financial liabilities.