About
RISC-V was designed to provide a highly modular and extensible instruction set, and includes a large and growing set of standard extensions. In addition, users may add their own custom extensions. This flexibility can be used to highly optimize a specialized design by including only the exact set of ISA features required for an application, but the same flexibility also leads to a combinatorial explosion in possible ISA choices. Profiles specify a much smaller common set of ISA choices that capture the most value for most users, and which thereby enable the software community to focus resources on building a rich software ecosystem with application and operating system portability across different implementations.
Each profile is built on a standard base ISA plus a set of mandatory ISA extensions, and provides a small set of standard ISA options to extend the mandatory components. Profiles provide a convenient shorthand for describing the ISA portions of hardware and software platforms, and also guide the development of common software toolchains shared by different platforms that use the same profile. The intent is that the software ecosystem focus on supporting the profiles' mandatory base and standard options, instead of attempting to support every possible combination of individual extensions. Similarly, hardware vendors should aim to structure their offerings around standard profiles to increase the likelihood their designs will have mainstream software support.
Refer, https://github.com/riscv/riscv-profiles/blob/main/profiles.adoc