If you ever “imported contacts”, perhaps from your GMail address book, then LinkedIn will offer you those repeatedly as new connections to “invite” to your network.

If you want to stop that, go to https://www.linkedin.com/mynetwork/contacts/imported/ then select all and Delete them. Note that this will not delete anyone from your LinkedIn connections, just the pointless email contacts.

If everything went well, the above URL should now display something like “You don’t have any imported contacts”. Congratulations!

To enter symbols and letters that are not on your keyboard, GTK applications on Linux offer something like Windows ALT codes, but for all Unicode characters, including the latest emojis.

Hold down CTRL-SHIFT-u and you will see an underlined u character that is waiting for input. Type the hexadecimal Unicode value and press space.

http://unicode.org/charts/ is a full collection of charts that list all Unicode characters with their codes.

Here is a cheat sheet for German:

Letter	Hex code
Ä	c4
ä	e4
Ö	d6
ö	f6
Ü	dc
ü	fc
ß	df
€	20ac

And here some emojis from the official Unicode chart:

Emoji	Hex code	Name
🙃	1f643	Upside-down face
💣	1f4a3	Bomb
🤡	1f921	Clown face

enter symbols and letters that are not on your keyboard