Documentation of item types differ slightly when looking at API methods for history.get and item object.

Item object:

Possible values: 
0 - numeric float; 
1 - character; 
2 - log; 
3 - numeric unsigned; 
4 - text.

History get method

Possible values: 
0 - float; 
1 - string; 
2 - log; 
3 - integer; 
4 - text. 

Would be nice to have them with the same text.

Pages related:
https://www.zabbix.com/documentation/2.4/manual/api/reference/history/get
https://www.zabbix.com/documentation/3.0/manual/api/reference/history/get
https://www.zabbix.com/documentation/2.4/manual/api/reference/item/object
https://www.zabbix.com/documentation/3.0/manual/api/reference/item/object