They are all legit file extensions:

*.sys - Files with the .sys extension are Windows System Files.

*.conf - Files that contain the .conf file extension are configuration files that are used to store the configuration and settings for a variety of different computer processes and applications.

*.spec - SPEC file is a RPM Package Specification. Red Hat Package Manager (RPM) is a package management system. RPM was intended primarily for Linux distributions.

*.y - Developer file used by Yacc (Yet Another Compiler-Compiler), a program used to generate source code parsers; contains formal declarations for how a programming language is defined; used for generating parsers for various languages.

.conf is a common file extension in Linux for a configuration file.

.spec is file extension for Red Hat package manger (RPM) builds.

.y is a spec file for yacc, a utility to compile compilers. Similar to a make file.