I'll correct myself before someone else does.
The TEXT of the definition is in SYSIBM.SYVIEWS and that is the only object
that has it like that.
So I guess your answer should be View only.
Apologies, Pierre.

In other words, the DDL for CREATE VIEW is stored explicitly in the DB2
Catalog.

For other objects, the DDL is not stored explicitly but the detailed
description of the object is found in the appropriate tables of the catalog.
For instance, if you look at SYSIBM.SYSTABLES, you will find all of the
attributes of every table in your database; each attribute is stored in a
separate column. Therefore, the exact DDL that was used to create these
objects is not kept but all of the information is available by reading the
catalog tables and views.

Since the real DDL is more convenient in some cases than the catalog
definitions, many DBAs store all DDL that get executed. In most shops, the
DBAs create all of the higher-level objects and use scripts to create the
objects. They keep the scripts after they have been executed. Then they have
both the original script, which shows the real DDL, and can get all of the
details from the catalog as well.

--
Rhino

You can find this in your DB2 Admin. reference Handdbook where all the
tables are described.
The SYSIBM.SYSTABLES catalog tables has a column that identifies the type of
object (V=View,T=Table,A=Alias) as well as a column PACKED_DESC which has a
compacted definition of the object. There's also an INDEX_DESC column in
SYSIBM.SYSINDEXES.
I believe but not definite that this where the db2look utility gets its info
when you use it to extract the DDL from an object
As a matter of fact, it has add'l columns, REL_DESC, TRIG_DESC,AST_DESC, and
so on where what is related to the table is stored.

To answer your question, I'd say all of the above as mentioned in your
question.
HTH,  Pierre.