Source: You Don't Know JS: this & Object Prototypes by Kyle Simpson (2014)
This mechanism is often called "prototypal inheritance" (we'll explore the code in detail shortly), which is commonly said to be the dynamic-language version of "classical inheritance". It's an attempt to piggy-back on the common understanding of what "inheritance" means in the class-oriented world, but tweak (read: pave over) the understood semantics, to fit dynamic scripting.
As I understand it, the part that begins with but tweak is just insertion text, kind of like a parenthetical statement. So, to fit dynamic scripting is the continuation of it's an attempt to piggy-back on the common understanding of what "inheritance" means in the class-oriented world (to fit dynamic scripting). What I have a problem with here is how exactly does that insertion text fit in with the rest of the sentence? What exactly do you think but tweak etc means? Is the author talking directly to me? Should I tweak the understood semantics? I don't fully grok the aspect it is used in.