5.3.0.3 - Xubuntu 16.04.1, Window 10 32/64bit
In new LO 5.3 some of menu items are not localized to czech in czech localization.
Here is list of yet found items:

LibreOffice central
Soubor:
- Open remote file...
- Sign of existing PDF
- Save remote file
Nápověda:
- Get help online...
- User guides...
- Start in safe mode...
Writer
Soubor:
- Open remote file...
- Šablony
	- Merge Templates
- Save remote file
- Export as PDF
- Odeslat
	- E-mail Document
- Digital signatures
	- Sign existing PDF
Úpravy:
- Sledování změn 
	- Manage 
	- Previous
	- Next
	- Accept
	- Reject
	- Protect
	- Compare document...
	- Merge document...
Zobrazit:
- Nástrojové lišty
	- Arrows
	- TSCP Classification
- Comments
- Formatting marks
- Mřižka a vodítka
	- Display grid
- Styles and formatting
Vložit:
- Page break
- Multimédia
	- Audio or Video
- Tvar
	- Arrow
	- Star
	- Callout
	- Flowchart
- Link
- Special Character...
- Poznámka pod čarou a vysvětlivka
	- Footnote
	- Endnote
- Field
Formát:
- Clone formatting
- Clear direct formatting
- Obrázek
	- Crop
- Name
- Description
Styly:
- Edit style...
- Update style
- New style...
- Styles and formatting
Tabulka:
- Insert table...
Nástroje:
- Spelling and Grammar...
- Automatic spell checking
Nápověda:
- User Guides...
- Get help online...
- Restart in safe mode...
Calc (navíc proti Writeru):
Úpravy:
- Select
- Compare document...
- Merge document..
Vložit:
- Objekt
	- Chart from file...
Formát:
- Rozestupy
	- Increase Indent
	- Decrease Indent
- Chart
Impress (kromě Writer a Calc)
Vložit:
- Audio or Video
Formát:
- Obrázek:
	- Crop dialog...