We currently ask for anything above 3.2 GL contexts, but we're still using GLSL 1.50 shaders all over the place. If a GL driver supports GL 3.2+ and GLSL 1.50 only then we'd be in trouble, but the chances of that happening are really small.
According to docs and Intel legacy drivers, GLSL version 130 is for GL 3.0 not GL 2.0/2.1 Validated files with reference compiler from https://www.khronos.org/opengles/sdk/tools/Reference-Compiler/
Having the shaders inlined as C strings makes them harder to edit and maintain.