@Everyone ChestESP 1.2 is now available, with support for both Fabric and NeoForge as well as all the latest Minecraft 1.21.x versions. Download it here: https://www.wimods.net/chestesp/chestesp-1-2/

Changelog

Added an "Include normal chests" option so you can turn off the ESP on normal chests while still keeping it enabled on other containers. (#5)
ChestESP now includes ModMenu (v11.0.3 in Fabric 1.21 - 1.21.1, v12.0.0-beta.1 in Fabric 1.21.2 - 1.21.3) so you don't have to install it separately anymore.
ChestESP now includes Cloth Config (v15.0.140 in Fabric/NeoForge 1.21 - 1.21.1, v16.0.141 in Fabric/NeoForge 1.21.2 - 1.21.3) so you don't have to install it separately anymore.
If you already have a different version of ModMenu or Cloth Config installed (e.g. from a modpack), Fabric/NeoForge will prioritize your version over the one that comes with ChestESP, so you don't have to worry about version conflicts.
Added automated testing (in both Fabric and NeoForge versions) to make sure ChestESP keeps working correctly. Every time ChestESP changes or is ported to a new Minecraft version, GitHub Actions will run the mod and take screenshots of chests with various settings. While I still do manual testing too, I can't possibly check every type of chest in every Minecraft version with every ChestESP setting, so this is a huge help.
You can view the automated test results in the Actions tab of ChestESP's GitHub repo (if you're logged into a GitHub account). You can also run this test on your own computer by adding -Dchestesp.e2eTest to your JVM arguments (the results will appear in your screenshots folder, not on GitHub).