private void appendInterfaceDeclaration(@Nonnull Printer out) {
		int acc = classInfo.getAccess();

		// Get flag-set and remove 'interface' and 'abstract'.
		// We will add 'interface' ourselves, and 'abstract' is redundant.
		Set<AccessFlag> flagSet = AccessFlag.getApplicableFlags(AccessFlag.Type.CLASS, acc);
		flagSet.remove(AccessFlag.ACC_INTERFACE);
		flagSet.remove(AccessFlag.ACC_ABSTRACT);
		String decFlagsString = AccessFlag.sortAndToString(AccessFlag.Type.CLASS, flagSet);
		StringBuilder sb = new StringBuilder();
		if (decFlagsString.isBlank()) {
			sb.append("interface ");
		} else {
			sb.append(decFlagsString)
					.append(" interface ");
		}
		sb.append(format.filter(classInfo.getName()));
		if (!classInfo.getInterfaces().isEmpty()) {
			// Interfaces use 'extends' rather than 'implements'.
			sb.append(" extends ");
			String interfaces = classInfo.getInterfaces().stream()
					.map(format::filter)
					.collect(Collectors.joining(", "));
			sb.append(interfaces);
		}
		out.appendLine(sb.toString());
	}
Appends the interface formatted declaration to the output.

@param out
		Printer to write to.
recaf-core/src/main/java/software/coley/recaf/services/decompile/fallback/print/ClassPrinter.java