src/vs/platform/quickinput/common/quickAccess.ts/QuickAccessRegistry/registerQuickAccessProvider
class QuickAccessRegistry:	registerQuickAccessProvider(provider: IQuickAccessProviderDescriptor): IDisposable {

		// Extract the default provider when no prefix is present
		if (provider.prefix.length === 0) {
			this.defaultProvider = provider;
		} else {
			this.providers.push(provider);
		}

		// sort the providers by decreasing prefix length, such that longer
		// prefixes take priority: 'ext' vs 'ext install' - the latter should win
		this.providers.sort((providerA, providerB) => providerB.prefix.length - providerA.prefix.length);

		return toDisposable(() => {
			this.providers.splice(this.providers.indexOf(provider), 1);

			if (this.defaultProvider === provider) {
				this.defaultProvider = undefined;
			}
		});
	}