Yes, indeed there was a reason for that. 😉
With this option the HTML source code is read, modified (some parts removed*) and "written back" by LocalCDN to the browser tab. The last step is sometimes incorrect, because TextEncode() supports only the UTF-8 charset.
So if a website was originally written with a different charset (e.g. ISO-8859-1), LocalCDN has to convert the HTML source code. The problem is when the web server has to process user input (e.g. in a forum), because then display errors occur due to the different encoding. This does not change the function of the LocalCDN, but it looks ugly. Problems could also occur if these entries are to end up in a database.
Therefore, this feature is optional and can be activated if required (in cases when certain parts of the HTML source code prevent the exchange).
*A part that must be removed is called integrity and checks with a checksum if the loaded framework has been changed. Since LocalCDN bundles several versions, the checksum will rarely match. LocalCDN must therefore remove these parts so that the CDN frameworks can be replaced.
Thank you for a thorough and perfect explanation.
OT: I guess christmass might come much earlier this year 😄: https://bugzilla.mozilla.org/show_bug.cgi?id=1419459#c11
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