I am trying to build a custom RTL Bootstrap 5 (version 5 is compatible with RTLCSS) unsing webpack with your tool but it looks like the /*rtl:ignore*/ directive is ignored.

For example, this line: https://github.com/twbs/bootstrap/blob/f61a0218b36d915db80dc23635a9078e98e2e3e0/scss/_reboot.scss#L278

Should always render direction: ltr; but in my project, webpack-rtl-plugin converts it to direction: rtl;.

Am I missing something?

As indicated in the readme, in my project I added const WebpackRTLPlugin = require('webpack-rtl-plugin') at the top of my webpack.config.js.
And then, added the plugin new WebpackRTLPlugin() to webpeck.

Please note that if I remove the line to add WebpackRTLPlugin plugin, the result is a css file containing:
direction: ltr /* rtl:ignore */;