There is a 1.20/1.20.1 version of the mod now.
It even has new features - you can turn the mod on and off now using the F9 key (can be rebound). Or if you're short on keyboard keys, bind it to nothing, and use /clton and /cltoff to enable/disable it. So you can have it enabled normally, and turn it off if you want to rotate item frames, dye signs, or change sign texts. Also, there's an option to change the target of a left click, which was requested by someone who plays on a server where left-clicking some chests has a special meaning.
When downloading, please make sure to go to the Files tab, and download the version for your MineCraft version. The files have the MC Version in their names. The 1.16 mod version works with MC 1.16.1 but not with 1.16.2 and 1.16.3; the 1.16.2 mod works with MC 1.16.3 but not with earlier versions. Curseforge doesn't always show the correct versions on the main page.
Want to help translate this mod to your language?
You can help me translate this mod on https://crowdin.com/project/clickthrough. (The mod itself does not contain any text, but the configuration does).
Mod description
This mod helps you access containers (chests, shulker boxes, barrels, but also hoppers, dispensers, ...) that are marked with a sign or item frame. Right-clicking a sign or item frame that's attached to a container will open the container instead.
Unlike other similar mods, it's purely client side, so it works on any kind of server - vanilla, modded, or spigot/paper.
You can still rotate items in item frames by sneaking and clicking them.
The same goes for signs that have some functionality attached by the server, for example, buy/sell signs on a server that has ChestShop or a similar plugin enabled.
There's an option to control dyeing signs - you can choose default behaviour (clicking a sign with a dye dyes that sign), or click through signs (clicking a sign with a dye opens the container behind, sneak-clicking dyes the sign).
If your server has a chest shop economy, clicking those signs will not open the container, but execute a trade instead. By default, a sign counts as a chest shop sign if there's one of [buy][shop][sell] in the first row, or a price tag (B 3, 7 S, B3:7S) in the third row.