Manuscript containing German slogans? (6)

I believe the answer is:

mottos

'slogans?' is the definition.
(a motto is a slogan or phrase)

'manuscript containing german' is the wordplay.
'manuscript' becomes 'ms' (abbreviation for manuscript).
'containing' means one lot of letters goes inside another.
'german' becomes 'otto' (I've seen this before).
'ms' going around 'otto' is 'MOTTOS'.

I've seen this clue in The Telegraph.

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