Do double byte characters behave the same in Salesforce Classic vs Lightning?

Question

I understand what is double-byte characters, but what I don't understand are:

1. What are the consequences of having double-byte characters input/stored/flow within a system (in this case Salesforce Lightning or Classic) and if the data needs to pass to other system? (e.g. will double byte characters have more chances of data corruption/or not displaying correctly?) Do these characters need to be converted to single byte to avoid this?
2. How to identify double-byte characters vs single byte (without writing codes if possible?)? Is it only Japan, Korea and China language that have double byte characters?
3. In Salesforce, do double byte characters automatically converted to Single Byte characters (Unicode?), when we input them in fields such as email/phone/etc? Is the behavior same in Classic and Lightning?

Appreciate if anyone could explain the above as I am fairly new in this. Thank you!

Answer 1

Salesforce represents all textual data as UTF-8.

UTF-8 is capable of encoding all 1,112,064 valid character code points in Unicode using one to four one-byte (8-bit) code units

There's no meaningful distinction between single-byte and double-byte characters on the Salesforce platform. International (non-ASCII) text is fully supported, and there's no particular distinction between the Classic and Lightning user experiences in this respect. Of course, any third-party components or integrations you use, and your local web browser, may add their own layers of support or non-support of international text encoded in UTF-8.

But in summary, whenever you interact with a Salesforce UI or API, you should expect text to be represented in UTF-8.