These tools are experimental and subject to breaking changes.

The AutotoolsToolchain is the toolchain generator for Autotools. It will generate shell scripts containing environment variable definitions that the autotools build system can understand.

The AutotooAutotoolsToolchainlsDeps generator can be used by name in conanfiles:
class Pkg(ConanFile):
    generators = "AutotoolsToolchain"

And it can also be fully instantiated in the conanfile generate() method:

from conans import ConanFile
from import AutotoolsToolchain

class App(ConanFile):
    settings = "os", "arch", "compiler", "build_type"

    def generate(self):
        tc = AutotoolsToolchain(self)

The AutotoolsToolchain will generate after a conan install command the or conanautotoolstoolchain.bat files:

$ conan install # default is Release
$ source
# or in Windows
$ conanautotoolstoolchain.bat

This generator will define aggregated variables CPPFLAGS, LDFLAGS, CXXFLAGS, CFLAGS that accumulate all dependencies information, including transitive dependencies, with flags like -stdlib=libstdc++, -std=gnu14, architecture flags, etc.