Codon phases shown on the Genome Browser

Gene transcript tracks, for example NCBI RefSeq and Gencode, show the codon phase of exons on mouse over. The text looks like this:

Transcript: ENST00000297261.7
Strand: -
Exon: Exon 2 of 3
Codon phase: start 0, end 1: out-of-frame exon

The codon phase specifies where in the coding sequence the intron falls in the codon that separates two exons:

This means that: