Numbers compare by value, so 항목2 comes before 항목10. That differs from plain string order.

IP addresses mixed with words.

IPv4 and IPv6 come before ordinary text, and in descending order they sit at the bottom.

Apple and apple are different lines. apple comes first.

It is not saved. Sorting stays in this tab.

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Hangul comes first, 10 follows 2, and IP addresses rise by their numeric value.

Drop duplicates Trim edges and blank lines

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Order: Ascending puts IP addresses, then Hangul, then Latin letters. Descending reverses that whole list, so IP addresses end at the bottom.
Numbers: 항목2 comes before 항목10. 10.0.0.2 comes before 10.0.0.10.
IP: An IPv4 address whose octets are all 255 or less comes first, then IPv6, then ordinary text. 10.0.0.256 is not an IP address.
Duplicates: Drop duplicates keeps one line by NFC. Apple and apple stay different.
Trim: With trim on, the line count leaves blank lines out. With trim off, a line that still has spaces is a different line.
Where: Sorting finishes in this browser. Nothing is uploaded.

With trim on, lines in exclude blank lines. Duplicates removed appears only while drop duplicates is on.

Names and addresses, one on each line, rise by Hangul order and by IP value.

If the same name was pasted twice, drop duplicates keeps the first line.

In the example, 10.0.0.2 sits above 10.0.0.10.

With drop duplicates on, 김철수 remains once and duplicates removed is 1.

EnteredNames and addresses

Q10 came before 2.: ANumbers compare by value, so 항목2 comes before 항목10. That differs from plain string order.
QIP addresses mixed with words.: AIPv4 and IPv6 come before ordinary text, and in descending order they sit at the bottom.
QWhat about capitals?: AApple and apple are different lines. apple comes first.
QIs it saved?: AIt is not saved. Sorting stays in this tab.