lol yes. At least in agency world, a common approach in the last X years has been that designers create entire pixel-perfect, component-based sources-of-truth in Figma (which evolve! they aren't delivered static and complete) -- these are also what the client sees and approves, or at the very least they see branded deck slides that incorporate the Figma designs. Anyways, front end then re-implements
from Figma into CSS, except it's usually best-approximation (not pixel-perfect) partially because, despite Figma allowing you to "copy CSS" for an element, it's unusable, almost inline CSS (and usually not aware of its ascendents and descendents, or any variables you're maintaining in CSS, or any class hierarchies, etc), and partially because the units of measurement aren't always identical on either side. You'll also often have multiple FE devs recreating components independently of each other (as a team effort), which can lead to drift and different implementations, which is fun. Then, depending upon the tech stack, FE might be building these components in something like Storybook [0] as a "front end source of truth", which then are either directly injected into a React or NextJS app or whatever, or sometimes they're partially or fully re-implemented
again into BE components in the CMS (ex. Sitefinity). Then people ask which one is
the source of truth, but really it's a chain of sources of truth that looks more like the telephone game than a canonical "brand bible". Then throw in any out-of-the-box future client efforts (say, a promotional landing page hosted outside of the main project) and you may have yet another reimplementation of part of the same design, but in a completely different system.
[0] https://storybook.js.org