src/vs/platform/extensionManagement/common/extensionsScannerService.ts/AbstractExtensionsScannerService/scanExtensionsUnderDevelopment
class AbstractExtensionsScannerService:	async scanExtensionsUnderDevelopment(scanOptions: ScanOptions, existingExtensions: IScannedExtension[]): Promise<IScannedExtension[]> {
		if (this.environmentService.isExtensionDevelopment && this.environmentService.extensionDevelopmentLocationURI) {
			const extensions = (await Promise.all(this.environmentService.extensionDevelopmentLocationURI.filter(extLoc => extLoc.scheme === Schemas.file)
				.map(async extensionDevelopmentLocationURI => {
					const input = await this.createExtensionScannerInput(extensionDevelopmentLocationURI, false, ExtensionType.User, true, scanOptions.language, false /* do not validate */);
					const extensions = await this.extensionsScanner.scanOneOrMultipleExtensions(input);
					return extensions.map(extension => {
						// Override the extension type from the existing extensions
						extension.type = existingExtensions.find(e => areSameExtensions(e.identifier, extension.identifier))?.type ?? extension.type;
						// Validate the extension
						return this.extensionsScanner.validate(extension, input);
					});
				})))
				.flat();
			return this.applyScanOptions(extensions, 'development', scanOptions, true);
		}
		return [];
	}