src/vs/workbench/contrib/welcome/gettingStarted/browser/gettingStartedService.ts/GettingStartedService/getStepOverrides
class GettingStartedService:	private async getStepOverrides(step: BuiltinGettingStartedStep, categoryId: string) {
		if (!this.tasExperimentService) { return; }

		const [title, description, media] = await Promise.all([
			this.tasExperimentService.getTreatment<string>(`gettingStarted.overrideStep.${step.id}.title`),
			this.tasExperimentService.getTreatment<string>(`gettingStarted.overrideStep.${step.id}.description`),
			this.tasExperimentService.getTreatment<string>(`gettingStarted.overrideStep.${step.id}.media`),
		]);

		if (!(title || description || media)) { return; }

		const existingCategory = assertIsDefined(this.gettingStartedContributions.get(categoryId));
		if (existingCategory.content.type === 'startEntry') { throw Error('Unexpected content type'); }
		const existingStep = assertIsDefined(existingCategory.content.steps.find(_step => _step.id === step.id));

		existingStep.title = title ?? existingStep.title;
		existingStep.description = description ? parseDescription(description) : existingStep.description;
		existingStep.media.path = media ? convertInternalMediaPathsToBrowserURIs(media) : existingStep.media.path;
		this._onDidChangeStep.fire(this.getStepProgress(existingStep));
	}