StarOffice Calc Spreadsheet Template (.stc)
The STC file extension stands for StarOffice Calc Spreadsheet Template. It is a binary file format used to create and save spreadsheet templates with settings such as page formatting, font size, margins, and charts. Originally supported by StarOffice software, it was later adopted by Apache OpenOffice before being replaced by the OTS format. STC files can be opened using OpenOffice Calc, and Planamesa NeoOffice.